POSIX - Perl interface to IEEE Std 1003.1
use POSIX ();
use POSIX qw(setsid);
use POSIX qw(:errno_h :fcntl_h);
printf "EINTR is %d\n", EINTR;
$sess_id = POSIX::setsid();
$fd = POSIX::open($path, O_CREAT|O_EXCL|O_WRONLY, 0644);
# note: that's a filedescriptor, *NOT* a filehandle
The POSIX module permits you to access all (or nearly all) the standard POSIX 1003.1 identifiers. Many of these identifiers have been given Perl-ish interfaces.
This document gives a condensed list of the features available in the POSIX module. Consult your operating system's manpages for general information on most features. Consult perlfunc for functions which are noted as being identical to Perl's builtin functions.
The first section describes POSIX functions from the 1003.1 specification. The second section describes some classes for signal objects, TTY objects, and other miscellaneous objects. The remaining sections list various constants and macros in an organization which roughly follows IEEE Std 1003.1b-1993.
Everything is exported by default (with a handful of exceptions). This is an unfortunate backwards compatibility feature and its use is strongly discouraged. You should either prevent the exporting (by saying use POSIX ();, as usual) and then use fully qualified names (e.g. POSIX::SEEK_END), or give an explicit import list. If you do neither and opt for the default (as in use POSIX;), you will import hundreds and hundreds of symbols into your namespace.
A few functions are not implemented because they are C specific. If you attempt to call these, they will print a message telling you that they aren't implemented, and suggest using the Perl equivalent, should one exist. For example, trying to access the setjmp() call will elicit the message "setjmp() is C-specific: use eval {} instead".
Furthermore, some evil vendors will claim 1003.1 compliance, but in fact are not so: they will not pass the PCTS (POSIX Compliance Test Suites). For example, one vendor may not define EDEADLK, or the semantics of the errno values set by open(2) might not be quite right. Perl does not attempt to verify POSIX compliance. That means you can currently successfully say "use POSIX", and then later in your program you find that your vendor has been lax and there's no usable ICANON macro after all. This could be construed to be a bug.
_exitThis is identical to the C function _exit(). It exits the program immediately which means among other things buffered I/O is not flushed.
Note that when using threads and in Linux this is not a good way to exit a thread because in Linux processes and threads are kind of the same thing (Note: while this is the situation in early 2003 there are projects under way to have threads with more POSIXly semantics in Linux). If you want not to return from a thread, detach the thread.
abortThis is identical to the C function abort(). It terminates the process with a SIGABRT signal unless caught by a signal handler or if the handler does not return normally (it e.g. does a longjmp).
absThis is identical to Perl's builtin abs() function, returning the absolute value of its numerical argument.
accessDetermines the accessibility of a file.
if( POSIX::access( "/", &POSIX::R_OK ) ){
print "have read permission\n";
}
Returns undef on failure. Note: do not use access() for security purposes. Between the access() call and the operation you are preparing for the permissions might change: a classic race condition.
acosThis is identical to the C function acos(), returning the arcus cosine of its numerical argument. See also Math::Trig.
acoshThis is identical to the C function acosh(), returning the hyperbolic arcus cosine of its numerical argument [C99]. See also Math::Trig.
alarmThis is identical to Perl's builtin alarm() function, either for arming or disarming the SIGARLM timer.
asctimeThis is identical to the C function asctime(). It returns a string of the form
"Fri Jun 2 18:22:13 2000\n\0"
and it is called thusly
$asctime = asctime($sec, $min, $hour, $mday, $mon,
$year, $wday, $yday, $isdst);
The $mon is zero-based: January equals 0. The $year is 1900-based: 2001 equals 101. $wday and $yday default to zero (and are usually ignored anyway), and $isdst defaults to -1.
asinThis is identical to the C function asin(), returning the arcus sine of its numerical argument. See also Math::Trig.
asinhThis is identical to the C function asinh(), returning the hyperbolic arcus sine of its numerical argument [C99]. See also Math::Trig.
assertUnimplemented, but you can use "die" in perlfunc and the Carp module to achieve similar things.
atanThis is identical to the C function atan(), returning the arcus tangent of its numerical argument. See also Math::Trig.
atanhThis is identical to the C function atanh(), returning the hyperbolic arcus tangent of its numerical argument [C99]. See also Math::Trig.
atan2This is identical to Perl's builtin atan2() function, returning the arcus tangent defined by its two numerical arguments, the y coordinate and the x coordinate. See also Math::Trig.
atexitNot implemented. atexit() is C-specific: use END {} instead, see perlmod.
atofNot implemented. atof() is C-specific. Perl converts strings to numbers transparently. If you need to force a scalar to a number, add a zero to it.
atoiNot implemented. atoi() is C-specific. Perl converts strings to numbers transparently. If you need to force a scalar to a number, add a zero to it. If you need to have just the integer part, see "int" in perlfunc.
atolNot implemented. atol() is C-specific. Perl converts strings to numbers transparently. If you need to force a scalar to a number, add a zero to it. If you need to have just the integer part, see "int" in perlfunc.
bsearchbsearch() not supplied. For doing binary search on wordlists, see Search::Dict.
callocNot implemented. calloc() is C-specific. Perl does memory management transparently.
cbrtThe cube root [C99].
ceilThis is identical to the C function ceil(), returning the smallest integer value greater than or equal to the given numerical argument.
chdirThis is identical to Perl's builtin chdir() function, allowing one to change the working (default) directory, see "chdir" in perlfunc.
chmodThis is identical to Perl's builtin chmod() function, allowing one to change file and directory permissions, see "chmod" in perlfunc.
chownThis is identical to Perl's builtin chown() function, allowing one to change file and directory owners and groups, see "chown" in perlfunc.
clearerrNot implemented. Use the method IO::Handle::clearerr() instead, to reset the error state (if any) and EOF state (if any) of the given stream.
clockThis is identical to the C function clock(), returning the amount of spent processor time in microseconds.
closeClose the file. This uses file descriptors such as those obtained by calling POSIX::open.
$fd = POSIX::open( "foo", &POSIX::O_RDONLY );
POSIX::close( $fd );
Returns undef on failure.
See also "close" in perlfunc.
closedirThis is identical to Perl's builtin closedir() function for closing a directory handle, see "closedir" in perlfunc.
cosThis is identical to Perl's builtin cos() function, for returning the cosine of its numerical argument, see "cos" in perlfunc. See also Math::Trig.
coshThis is identical to the C function cosh(), for returning the hyperbolic cosine of its numeric argument. See also Math::Trig.
copysignReturns x but with the sign of y [C99].
$x_with_sign_of_y = POSIX::copysign($x, $y);
See also "signbit".
creatCreate a new file. This returns a file descriptor like the ones returned by POSIX::open. Use POSIX::close to close the file.
$fd = POSIX::creat( "foo", 0611 );
POSIX::close( $fd );
See also "sysopen" in perlfunc and its O_CREAT flag.
ctermidGenerates the path name for the controlling terminal.
$path = POSIX::ctermid();
ctimeThis is identical to the C function ctime() and equivalent to asctime(localtime(...)), see "asctime" and "localtime".
cuseridGet the login name of the owner of the current process.
$name = POSIX::cuserid();
difftimeThis is identical to the C function difftime(), for returning the time difference (in seconds) between two times (as returned by time()), see "time".
divNot implemented. div() is C-specific, use "int" in perlfunc on the usual / division and the modulus %.
dupThis is similar to the C function dup(), for duplicating a file descriptor.
This uses file descriptors such as those obtained by calling POSIX::open.
Returns undef on failure.
dup2This is similar to the C function dup2(), for duplicating a file descriptor to an another known file descriptor.
This uses file descriptors such as those obtained by calling POSIX::open.
Returns undef on failure.
erfThe error function [C99].
erfcThe complementary error function [C99].
errnoReturns the value of errno.
$errno = POSIX::errno();
This identical to the numerical values of the $!, see "$ERRNO" in perlvar.
execlNot implemented. execl() is C-specific, see "exec" in perlfunc.
execleNot implemented. execle() is C-specific, see "exec" in perlfunc.
execlpNot implemented. execlp() is C-specific, see "exec" in perlfunc.
execvNot implemented. execv() is C-specific, see "exec" in perlfunc.
execveNot implemented. execve() is C-specific, see "exec" in perlfunc.
execvpNot implemented. execvp() is C-specific, see "exec" in perlfunc.
exitThis is identical to Perl's builtin exit() function for exiting the program, see "exit" in perlfunc.
expThis is identical to Perl's builtin exp() function for returning the exponent (e-based) of the numerical argument, see "exp" in perlfunc.
expm1Equivalent to exp(x) - 1, but more precise for small argument values [C99].
See also "log1p".
fabsThis is identical to Perl's builtin abs() function for returning the absolute value of the numerical argument, see "abs" in perlfunc.
fcloseNot implemented. Use method IO::Handle::close() instead, or see "close" in perlfunc.
fcntlThis is identical to Perl's builtin fcntl() function, see "fcntl" in perlfunc.
fdopenNot implemented. Use method IO::Handle::new_from_fd() instead, or see "open" in perlfunc.
feofNot implemented. Use method IO::Handle::eof() instead, or see "eof" in perlfunc.
ferrorNot implemented. Use method IO::Handle::error() instead.
fflushNot implemented. Use method IO::Handle::flush() instead. See also "$OUTPUT_AUTOFLUSH" in perlvar.
fgetcNot implemented. Use method IO::Handle::getc() instead, or see "read" in perlfunc.
fgetposNot implemented. Use method IO::Seekable::getpos() instead, or see "seek" in perlfunc.
fgetsNot implemented. Use method IO::Handle::gets() instead. Similar to <>, also known as "readline" in perlfunc.
filenoNot implemented. Use method IO::Handle::fileno() instead, or see "fileno" in perlfunc.
floorThis is identical to the C function floor(), returning the largest integer value less than or equal to the numerical argument.
fdim"Positive difference", x - y if x > y, zero otherwise [C99].
fegetroundReturns the current floating point rounding mode, one of
FE_TONEAREST FE_TOWARDZERO FE_UPWARD FE_UPWARD
FE_TONEAREST is like "round", FE_TOWARDZERO is like "trunc" [C99].
fesetroundSets the floating point rounding mode, see "fegetround" [C99].
fma"Fused multiply-add", x * y + z, possibly faster (and less lossy) than the explicit two operations [C99].
my $fused = POSIX::fma($x, $y, $z);
fmaxMaximum of x and y, except when either is NaN, returns the other [C99].
my $min = POSIX::fmax($x, $y);
fminMinimum of x and y, except when either is NaN, returns the other [C99].
my $min = POSIX::fmin($x, $y);
fmodThis is identical to the C function fmod().
$r = fmod($x, $y);
It returns the remainder $r = $x - $n*$y, where $n = trunc($x/$y). The $r has the same sign as $x and magnitude (absolute value) less than the magnitude of $y.
fopenNot implemented. Use method IO::File::open() instead, or see "open" in perlfunc.
forkThis is identical to Perl's builtin fork() function for duplicating the current process, see "fork" in perlfunc and perlfork if you are in Windows.
fpathconfRetrieves the value of a configurable limit on a file or directory. This uses file descriptors such as those obtained by calling POSIX::open.
The following will determine the maximum length of the longest allowable pathname on the filesystem which holds /var/foo.
$fd = POSIX::open( "/var/foo", &POSIX::O_RDONLY );
$path_max = POSIX::fpathconf($fd, &POSIX::_PC_PATH_MAX);
Returns undef on failure.
fpclassifyReturns one of
FP_NORMAL FP_ZERO FP_SUBNORMAL FP_INFINITE FP_NAN
telling the class of the argument [C99]. FP_INFINITE is positive or negative infinity, FP_NAN is not-a-number. FP_SUBNORMAL means subnormal numbers (also known as denormals), very small numbers with low precision. FP_ZERO is zero. FP_NORMAL is all the rest.
fprintfNot implemented. fprintf() is C-specific, see "printf" in perlfunc instead.
fputcNot implemented. fputc() is C-specific, see "print" in perlfunc instead.
fputsNot implemented. fputs() is C-specific, see "print" in perlfunc instead.
freadNot implemented. fread() is C-specific, see "read" in perlfunc instead.
freeNot implemented. free() is C-specific. Perl does memory management transparently.
freopenNot implemented. freopen() is C-specific, see "open" in perlfunc instead.
frexpReturn the mantissa and exponent of a floating-point number.
($mantissa, $exponent) = POSIX::frexp( 1.234e56 );
fscanfNot implemented. fscanf() is C-specific, use <> and regular expressions instead.
fseekNot implemented. Use method IO::Seekable::seek() instead, or see "seek" in perlfunc.
fsetposNot implemented. Use method IO::Seekable::setpos() instead, or seek "seek" in perlfunc.
fstatGet file status. This uses file descriptors such as those obtained by calling POSIX::open. The data returned is identical to the data from Perl's builtin stat function.
$fd = POSIX::open( "foo", &POSIX::O_RDONLY );
@stats = POSIX::fstat( $fd );
fsyncNot implemented. Use method IO::Handle::sync() instead.
ftellNot implemented. Use method IO::Seekable::tell() instead, or see "tell" in perlfunc.
fwriteNot implemented. fwrite() is C-specific, see "print" in perlfunc instead.
getcThis is identical to Perl's builtin getc() function, see "getc" in perlfunc.
getcharReturns one character from STDIN. Identical to Perl's getc(), see "getc" in perlfunc.
getcwdReturns the name of the current working directory. See also Cwd.
getegidReturns the effective group identifier. Similar to Perl' s builtin variable $(, see "$EGID" in perlvar.
getenvReturns the value of the specified environment variable. The same information is available through the %ENV array.
geteuidReturns the effective user identifier. Identical to Perl's builtin $> variable, see "$EUID" in perlvar.
getgidReturns the user's real group identifier. Similar to Perl's builtin variable $), see "$GID" in perlvar.
getgrgidThis is identical to Perl's builtin getgrgid() function for returning group entries by group identifiers, see "getgrgid" in perlfunc.
getgrnamThis is identical to Perl's builtin getgrnam() function for returning group entries by group names, see "getgrnam" in perlfunc.
getgroupsReturns the ids of the user's supplementary groups. Similar to Perl's builtin variable $), see "$GID" in perlvar.
getloginThis is identical to Perl's builtin getlogin() function for returning the user name associated with the current session, see "getlogin" in perlfunc.
getpayloaduse POSIX ':nan_payload';
getpayload($var)
Returns the NaN payload.
Note the API instability warning in "setpayload".
See "nan" for more discussion about NaN.
getpgrpThis is identical to Perl's builtin getpgrp() function for returning the process group identifier of the current process, see "getpgrp" in perlfunc.
getpidReturns the process identifier. Identical to Perl's builtin variable $$, see "$PID" in perlvar.
getppidThis is identical to Perl's builtin getppid() function for returning the process identifier of the parent process of the current process , see "getppid" in perlfunc.
getpwnamThis is identical to Perl's builtin getpwnam() function for returning user entries by user names, see "getpwnam" in perlfunc.
getpwuidThis is identical to Perl's builtin getpwuid() function for returning user entries by user identifiers, see "getpwuid" in perlfunc.
getsReturns one line from STDIN, similar to <>, also known as the readline() function, see "readline" in perlfunc.
NOTE: if you have C programs that still use gets(), be very afraid. The gets() function is a source of endless grief because it has no buffer overrun checks. It should never be used. The fgets() function should be preferred instead.
getuidReturns the user's identifier. Identical to Perl's builtin $< variable, see "$UID" in perlvar.
gmtimeThis is identical to Perl's builtin gmtime() function for converting seconds since the epoch to a date in Greenwich Mean Time, see "gmtime" in perlfunc.
hypotEquivalent to sqrt(x * x + y * y) except more stable on very large or very small arguments [C99].
ilogbInteger binary logarithm [C99]
For example ilogb(20) is 4, as an integer.
See also "logb".
InfThe infinity as a constant:
use POSIX qw(Inf);
my $pos_inf = +Inf; # Or just Inf.
my $neg_inf = -Inf;
See also "isinf", and "fpclassify".
isalnumThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:alnum:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
isalphaThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:alpha:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
isattyReturns a boolean indicating whether the specified filehandle is connected to a tty. Similar to the -t operator, see "-X" in perlfunc.
iscntrlThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:cntrl:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
isdigitThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:digit:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
isfiniteReturns true if the argument is a finite number (that is, not an infinity, or the not-a-number) [C99].
See also "isinf", "isnan", and "fpclassify".
isgraphThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:graph:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
isgreater(Also isgreaterequal, isless, islessequal, islessgreater, isunordered)
Floating point comparisons which handle the NaN [C99].
isinfReturns true if the argument is an infinity (positive or negative) [C99].
See also "Inf", "isnan", "isfinite", and "fpclassify".
islowerThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:lower:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
isnanReturns true if the argument is NaN (not-a-number) [C99].
Note that you cannot test for "NaN-ness" with
$x == $x
since the NaN is not equivalent to anything, including itself.
See also "nan", "NaN", "isinf", and "fpclassify".
isnormalReturns true if the argument is normal (that is, not a subnormal/denormal, and not an infinity, or a not-a-number) [C99].
See also "isfinite", and "fpclassify".
isprintThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:print:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
ispunctThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:punct:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
issignalinguse POSIX ':nan_payload';
issignaling($var, $payload)
Return true if the argument is a signaling NaN.
Note the API instability warning in "setpayload".
See "nan" for more discussion about NaN.
isspaceThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:space:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
isupperThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:upper:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
isxdigitThis function has been removed as of v5.24. It was very similar to matching against qr/ ^ [[:xdigit:]]+ $ /x, which you should convert to use instead. See "POSIX Character Classes" in perlrecharclass.
j0j1jny0y1ynThe Bessel function of the first kind of the order zero.
killThis is identical to Perl's builtin kill() function for sending signals to processes (often to terminate them), see "kill" in perlfunc.
labsNot implemented. (For returning absolute values of long integers.) labs() is C-specific, see "abs" in perlfunc instead.
lchownThis is identical to the C function, except the order of arguments is consistent with Perl's builtin chown() with the added restriction of only one path, not a list of paths. Does the same thing as the chown() function but changes the owner of a symbolic link instead of the file the symbolic link points to.
POSIX::lchown($uid, $gid, $file_path);
ldexpThis is identical to the C function ldexp() for multiplying floating point numbers with powers of two.
$x_quadrupled = POSIX::ldexp($x, 2);
ldivNot implemented. (For computing dividends of long integers.) ldiv() is C-specific, use / and int() instead.
lgammaThe logarithm of the Gamma function [C99].
See also "tgamma".
log1pEquivalent to log(1 + x), but more stable results for small argument values [C99].
log2Logarithm base two [C99].
See also "expm1".
logbInteger binary logarithm [C99].
For example logb(20) is 4, as a floating point number.
See also "ilogb".
linkThis is identical to Perl's builtin link() function for creating hard links into files, see "link" in perlfunc.
localeconvGet numeric formatting information. Returns a reference to a hash containing the current underlying locale's formatting values. Users of this function should also read perllocale, which provides a comprehensive discussion of Perl locale handling, including a section devoted to this function.
Here is how to query the database for the de (Deutsch or German) locale.
my $loc = POSIX::setlocale( &POSIX::LC_ALL, "de" );
print "Locale: \"$loc\"\n";
my $lconv = POSIX::localeconv();
foreach my $property (qw(
decimal_point
thousands_sep
grouping
int_curr_symbol
currency_symbol
mon_decimal_point
mon_thousands_sep
mon_grouping
positive_sign
negative_sign
int_frac_digits
frac_digits
p_cs_precedes
p_sep_by_space
n_cs_precedes
n_sep_by_space
p_sign_posn
n_sign_posn
int_p_cs_precedes
int_p_sep_by_space
int_n_cs_precedes
int_n_sep_by_space
int_p_sign_posn
int_n_sign_posn
))
{
printf qq(%s: "%s",\n),
$property, $lconv->{$property};
}
The members whose names begin with int_p_ and int_n_ were added by POSIX.1-2008 and are only available on systems that support them.
localtimeThis is identical to Perl's builtin localtime() function for converting seconds since the epoch to a date see "localtime" in perlfunc.
logThis is identical to Perl's builtin log() function, returning the natural (e-based) logarithm of the numerical argument, see "log" in perlfunc.
log10This is identical to the C function log10(), returning the 10-base logarithm of the numerical argument. You can also use
sub log10 { log($_[0]) / log(10) }
or
sub log10 { log($_[0]) / 2.30258509299405 }
or
sub log10 { log($_[0]) * 0.434294481903252 }
longjmpNot implemented. longjmp() is C-specific: use "die" in perlfunc instead.
lseekMove the file's read/write position. This uses file descriptors such as those obtained by calling POSIX::open.
$fd = POSIX::open( "foo", &POSIX::O_RDONLY );
$off_t = POSIX::lseek( $fd, 0, &POSIX::SEEK_SET );
Returns undef on failure.
lrintDepending on the current floating point rounding mode, rounds the argument either toward nearest (like "round"), toward zero (like "trunc"), downward (toward negative infinity), or upward (toward positive infinity) [C99].
For the rounding mode, see "fegetround".
lroundLike "round", but as integer, as opposed to floating point [C99].
See also "ceil", "floor", "trunc".
Owing to an oversight, this is not currently exported by default, or as part of the :math_h_c99 export tag; importing it must therefore be done by explicit name. This will be changed in Perl 5.26.
mallocNot implemented. malloc() is C-specific. Perl does memory management transparently.
mblenThis is identical to the C function mblen().
Core Perl does not have any support for the wide and multibyte characters of the C standards, except under UTF-8 locales, so this might be a rather useless function.
However, Perl supports Unicode, see perluniintro.
mbstowcsThis is identical to the C function mbstowcs().
See "mblen".
mbtowcThis is identical to the C function mbtowc().
See "mblen".
memchrNot implemented. memchr() is C-specific, see "index" in perlfunc instead.
memcmpNot implemented. memcmp() is C-specific, use eq instead, see perlop.
memcpyNot implemented. memcpy() is C-specific, use =, see perlop, or see "substr" in perlfunc.
memmoveNot implemented. memmove() is C-specific, use =, see perlop, or see "substr" in perlfunc.
memsetNot implemented. memset() is C-specific, use x instead, see perlop.
mkdirThis is identical to Perl's builtin mkdir() function for creating directories, see "mkdir" in perlfunc.
mkfifoThis is similar to the C function mkfifo() for creating FIFO special files.
if (mkfifo($path, $mode)) { ....
Returns undef on failure. The $mode is similar to the mode of mkdir(), see "mkdir" in perlfunc, though for mkfifo you must specify the $mode.
mktimeConvert date/time info to a calendar time.
Synopsis:
mktime(sec, min, hour, mday, mon, year, wday = 0,
yday = 0, isdst = -1)
The month (mon), weekday (wday), and yearday (yday) begin at zero, i.e., January is 0, not 1; Sunday is 0, not 1; January 1st is 0, not 1. The year (year) is given in years since 1900; i.e., the year 1995 is 95; the year 2001 is 101. Consult your system's mktime() manpage for details about these and the other arguments.
Calendar time for December 12, 1995, at 10:30 am.
$time_t = POSIX::mktime( 0, 30, 10, 12, 11, 95 );
print "Date = ", POSIX::ctime($time_t);
Returns undef on failure.
modfReturn the integral and fractional parts of a floating-point number.
($fractional, $integral) = POSIX::modf( 3.14 );
See also "round".
NaNThe not-a-number as a constant:
use POSIX qw(NaN);
my $nan = NaN;
See also "nan", /isnan, and "fpclassify".
nanmy $nan = nan();
Returns NaN, not-a-number [C99].
The returned NaN is always a quiet NaN, as opposed to signaling.
With an argument, can be used to generate a NaN with payload. The argument is first interpreted as a floating point number, but then any fractional parts are truncated (towards zero), and the value is interpreted as an unsigned integer. The bits of this integer are stored in the unused bits of the NaN.
The result has a dual nature: it is a NaN, but it also carries the integer inside it. The integer can be retrieved with "getpayload". Note, though, that the payload is not propagated, not even on copies, and definitely not in arithmetic operations.
How many bits fit in the NaN depends on what kind of floating points are being used, but on the most common platforms (64-bit IEEE 754, or the x86 80-bit long doubles) there are 51 and 61 bits available, respectively. (There would be 52 and 62, but the quiet/signaling bit of NaNs takes away one.) However, because of the floating-point-to- integer-and-back conversions, please test carefully whether you get back what you put in. If your integers are only 32 bits wide, you probably should not rely on more than 32 bits of payload.
Whether a "signaling" NaN is in any way different from a "quiet" NaN, depends on the platform. Also note that the payload of the default NaN (no argument to nan()) is not necessarily zero, use setpayload to explicitly set the payload. On some platforms like the 32-bit x86, (unless using the 80-bit long doubles) the signaling bit is not supported at all.
See also "isnan", "NaN", "setpayload" and "issignaling".
nearbyintReturns the nearest integer to the argument, according to the current rounding mode (see "fegetround") [C99].
nextafterReturns the next representable floating point number after x in the direction of y [C99].
my $nextafter = POSIX::nextafter($x, $y);
Like "nexttoward", but potentially less accurate.
nexttowardReturns the next representable floating point number after x in the direction of y [C99].
my $nexttoward = POSIX::nexttoward($x, $y);
Like "nextafter", but potentially more accurate.
niceThis is similar to the C function nice(), for changing the scheduling preference of the current process. Positive arguments mean a more polite process, negative values a more needy process. Normal (non-root) user processes can only change towards being more polite.
Returns undef on failure.
offsetofNot implemented. offsetof() is C-specific, you probably want to see "pack" in perlfunc instead.
openOpen a file for reading for writing. This returns file descriptors, not Perl filehandles. Use POSIX::close to close the file.
Open a file read-only with mode 0666.
$fd = POSIX::open( "foo" );
Open a file for read and write.
$fd = POSIX::open( "foo", &POSIX::O_RDWR );
Open a file for write, with truncation.
$fd = POSIX::open(
"foo", &POSIX::O_WRONLY | &POSIX::O_TRUNC
);
Create a new file with mode 0640. Set up the file for writing.
$fd = POSIX::open(
"foo", &POSIX::O_CREAT | &POSIX::O_WRONLY, 0640
);
Returns undef on failure.
See also "sysopen" in perlfunc.
opendirOpen a directory for reading.
$dir = POSIX::opendir( "/var" );
@files = POSIX::readdir( $dir );
POSIX::closedir( $dir );
Returns undef on failure.
pathconfRetrieves the value of a configurable limit on a file or directory.
The following will determine the maximum length of the longest allowable pathname on the filesystem which holds /var.
$path_max = POSIX::pathconf( "/var",
&POSIX::_PC_PATH_MAX );
Returns undef on failure.
pauseThis is similar to the C function pause(), which suspends the execution of the current process until a signal is received.
Returns undef on failure.
perrorThis is identical to the C function perror(), which outputs to the standard error stream the specified message followed by ": " and the current error string. Use the warn() function and the $! variable instead, see "warn" in perlfunc and "$ERRNO" in perlvar.
pipeCreate an interprocess channel. This returns file descriptors like those returned by POSIX::open.
my ($read, $write) = POSIX::pipe();
POSIX::write( $write, "hello", 5 );
POSIX::read( $read, $buf, 5 );
See also "pipe" in perlfunc.
powComputes $x raised to the power $exponent.
$ret = POSIX::pow( $x, $exponent );
You can also use the ** operator, see perlop.
printfFormats and prints the specified arguments to STDOUT. See also "printf" in perlfunc.
putcNot implemented. putc() is C-specific, see "print" in perlfunc instead.
putcharNot implemented. putchar() is C-specific, see "print" in perlfunc instead.
putsNot implemented. puts() is C-specific, see "print" in perlfunc instead.
qsortNot implemented. qsort() is C-specific, see "sort" in perlfunc instead.
raiseSends the specified signal to the current process. See also "kill" in perlfunc and the $$ in "$PID" in perlvar.
randNot implemented. rand() is non-portable, see "rand" in perlfunc instead.
readRead from a file. This uses file descriptors such as those obtained by calling POSIX::open. If the buffer $buf is not large enough for the read then Perl will extend it to make room for the request.
$fd = POSIX::open( "foo", &POSIX::O_RDONLY );
$bytes = POSIX::read( $fd, $buf, 3 );
Returns undef on failure.
See also "sysread" in perlfunc.
readdirThis is identical to Perl's builtin readdir() function for reading directory entries, see "readdir" in perlfunc.
reallocNot implemented. realloc() is C-specific. Perl does memory management transparently.
remainderGiven x and y, returns the value x - n*y, where n is the integer closest to x/y. [C99]
my $remainder = POSIX::remainder($x, $y)
See also "remquo".
removeThis is identical to Perl's builtin unlink() function for removing files, see "unlink" in perlfunc.
remquoLike "remainder" but also returns the low-order bits of the quotient (n) [C99]
(This is quite esoteric interface, mainly used to implement numerical algorithms.)
renameThis is identical to Perl's builtin rename() function for renaming files, see "rename" in perlfunc.
rewindSeeks to the beginning of the file.
rewinddirThis is identical to Perl's builtin rewinddir() function for rewinding directory entry streams, see "rewinddir" in perlfunc.
rintIdentical to "lrint".
rmdirThis is identical to Perl's builtin rmdir() function for removing (empty) directories, see "rmdir" in perlfunc.
roundReturns the integer (but still as floating point) nearest to the argument [C99].
scalbnReturns x * 2**y [C99].
scanfNot implemented. scanf() is C-specific, use <> and regular expressions instead, see perlre.
setgidSets the real group identifier and the effective group identifier for this process. Similar to assigning a value to the Perl's builtin $) variable, see "$EGID" in perlvar, except that the latter will change only the real user identifier, and that the setgid() uses only a single numeric argument, as opposed to a space-separated list of numbers.
setjmpNot implemented. setjmp() is C-specific: use eval {} instead, see "eval" in perlfunc.
setlocaleWARNING! Do NOT use this function in a thread. The locale will change in all other threads at the same time, and should your thread get paused by the operating system, and another started, that thread will not have the locale it is expecting. On some platforms, there can be a race leading to segfaults if two threads call this function nearly simultaneously.
Modifies and queries the program's underlying locale. Users of this function should read perllocale, whch provides a comprehensive discussion of Perl locale handling, knowledge of which is necessary to properly use this function. It contains a section devoted to this function. The discussion here is merely a summary reference for setlocale(). Note that Perl itself is almost entirely unaffected by the locale except within the scope of "use locale". (Exceptions are listed in "Not within the scope of "use locale"" in perllocale.)
The following examples assume
use POSIX qw(setlocale LC_ALL LC_CTYPE);
has been issued.
The following will set the traditional UNIX system locale behavior (the second argument "C").
$loc = setlocale( LC_ALL, "C" );
The following will query the current LC_CTYPE category. (No second argument means 'query'.)
$loc = setlocale( LC_CTYPE );
The following will set the LC_CTYPE behaviour according to the locale environment variables (the second argument ""). Please see your system's setlocale(3) documentation for the locale environment variables' meaning or consult perllocale.
$loc = setlocale( LC_CTYPE, "" );
The following will set the LC_COLLATE behaviour to Argentinian Spanish. NOTE: The naming and availability of locales depends on your operating system. Please consult perllocale for how to find out which locales are available in your system.
$loc = setlocale( LC_COLLATE, "es_AR.ISO8859-1" );
setpayloaduse POSIX ':nan_payload';
setpayload($var, $payload);
Sets the NaN payload of var.
NOTE: the NaN payload APIs are based on the latest (as of June 2015) proposed ISO C interfaces, but they are not yet a standard. Things may change.
See "nan" for more discussion about NaN.
See also "setpayloadsig", "isnan", "getpayload", and "issignaling".
setpayloadsiguse POSIX ':nan_payload';
setpayloadsig($var, $payload);
Like "setpayload" but also makes the NaN signaling.
Depending on the platform the NaN may or may not behave differently.
Note the API instability warning in "setpayload".
Note that because how the floating point formats work out, on the most common platforms signaling payload of zero is best avoided, since it might end up being identical to +Inf.
See also "nan", "isnan", "getpayload", and "issignaling".
setpgidThis is similar to the C function setpgid() for setting the process group identifier of the current process.
Returns undef on failure.
setsidThis is identical to the C function setsid() for setting the session identifier of the current process.
setuidSets the real user identifier and the effective user identifier for this process. Similar to assigning a value to the Perl's builtin $< variable, see "$UID" in perlvar, except that the latter will change only the real user identifier.
sigactionDetailed signal management. This uses POSIX::SigAction objects for the action and oldaction arguments (the oldaction can also be just a hash reference). Consult your system's sigaction manpage for details, see also POSIX::SigRt.
Synopsis:
sigaction(signal, action, oldaction = 0)
Returns undef on failure. The signal must be a number (like SIGHUP), not a string (like "SIGHUP"), though Perl does try hard to understand you.
If you use the SA_SIGINFO flag, the signal handler will in addition to the first argument, the signal name, also receive a second argument, a hash reference, inside which are the following keys with the following semantics, as defined by POSIX/SUSv3:
signo the signal number
errno the error number
code if this is zero or less, the signal was sent by
a user process and the uid and pid make sense,
otherwise the signal was sent by the kernel
The constants for specific code values can be imported individually or using the :signal_h_si_code tag.
The following are also defined by POSIX/SUSv3, but unfortunately not very widely implemented:
pid the process id generating the signal
uid the uid of the process id generating the signal
status exit value or signal for SIGCHLD
band band event for SIGPOLL
addr address of faulting instruction or memory
reference for SIGILL, SIGFPE, SIGSEGV or SIGBUS
A third argument is also passed to the handler, which contains a copy of the raw binary contents of the siginfo structure: if a system has some non-POSIX fields, this third argument is where to unpack() them from.
Note that not all siginfo values make sense simultaneously (some are valid only for certain signals, for example), and not all values make sense from Perl perspective, you should to consult your system's sigaction and possibly also siginfo documentation.
siglongjmpNot implemented. siglongjmp() is C-specific: use "die" in perlfunc instead.
signbitReturns zero for positive arguments, non-zero for negative arguments [C99].
sigpendingExamine signals that are blocked and pending. This uses POSIX::SigSet objects for the sigset argument. Consult your system's sigpending manpage for details.
Synopsis:
sigpending(sigset)
Returns undef on failure.
sigprocmaskChange and/or examine calling process's signal mask. This uses POSIX::SigSet objects for the sigset and oldsigset arguments. Consult your system's sigprocmask manpage for details.
Synopsis:
sigprocmask(how, sigset, oldsigset = 0)
Returns undef on failure.
Note that you can't reliably block or unblock a signal from its own signal handler if you're using safe signals. Other signals can be blocked or unblocked reliably.
sigsetjmpNot implemented. sigsetjmp() is C-specific: use eval {} instead, see "eval" in perlfunc.
sigsuspendInstall a signal mask and suspend process until signal arrives. This uses POSIX::SigSet objects for the signal_mask argument. Consult your system's sigsuspend manpage for details.
Synopsis:
sigsuspend(signal_mask)
Returns undef on failure.
sinThis is identical to Perl's builtin sin() function for returning the sine of the numerical argument, see "sin" in perlfunc. See also Math::Trig.
sinhThis is identical to the C function sinh() for returning the hyperbolic sine of the numerical argument. See also Math::Trig.
sleepThis is functionally identical to Perl's builtin sleep() function for suspending the execution of the current for process for certain number of seconds, see "sleep" in perlfunc. There is one significant difference, however: POSIX::sleep() returns the number of unslept seconds, while the CORE::sleep() returns the number of slept seconds.
sprintfThis is similar to Perl's builtin sprintf() function for returning a string that has the arguments formatted as requested, see "sprintf" in perlfunc.
sqrtThis is identical to Perl's builtin sqrt() function. for returning the square root of the numerical argument, see "sqrt" in perlfunc.
srandGive a seed the pseudorandom number generator, see "srand" in perlfunc.
sscanfNot implemented. sscanf() is C-specific, use regular expressions instead, see perlre.
statThis is identical to Perl's builtin stat() function for returning information about files and directories.
strcatNot implemented. strcat() is C-specific, use .= instead, see perlop.
strchrNot implemented. strchr() is C-specific, see "index" in perlfunc instead.
strcmpNot implemented. strcmp() is C-specific, use eq or cmp instead, see perlop.
strcollThis is identical to the C function strcoll() for collating (comparing) strings transformed using the strxfrm() function. Not really needed since Perl can do this transparently, see perllocale.
strcpyNot implemented. strcpy() is C-specific, use = instead, see perlop.
strcspnNot implemented. strcspn() is C-specific, use regular expressions instead, see perlre.
strerrorReturns the error string for the specified errno. Identical to the string form of $!, see "$ERRNO" in perlvar.
strftimeConvert date and time information to string. Returns the string.
Synopsis:
strftime(fmt, sec, min, hour, mday, mon, year,
wday = -1, yday = -1, isdst = -1)
The month (mon), weekday (wday), and yearday (yday) begin at zero, i.e., January is 0, not 1; Sunday is 0, not 1; January 1st is 0, not 1. The year (year) is given in years since 1900, i.e., the year 1995 is 95; the year 2001 is 101. Consult your system's strftime() manpage for details about these and the other arguments.
If you want your code to be portable, your format (fmt) argument should use only the conversion specifiers defined by the ANSI C standard (C89, to play safe). These are aAbBcdHIjmMpSUwWxXyYZ%. But even then, the results of some of the conversion specifiers are non-portable. For example, the specifiers aAbBcpZ change according to the locale settings of the user, and both how to set locales (the locale names) and what output to expect are non-standard. The specifier c changes according to the timezone settings of the user and the timezone computation rules of the operating system. The Z specifier is notoriously unportable since the names of timezones are non-standard. Sticking to the numeric specifiers is the safest route.
The given arguments are made consistent as though by calling mktime() before calling your system's strftime() function, except that the isdst value is not affected.
The string for Tuesday, December 12, 1995.
$str = POSIX::strftime( "%A, %B %d, %Y",
0, 0, 0, 12, 11, 95, 2 );
print "$str\n";
strlenNot implemented. strlen() is C-specific, use length() instead, see "length" in perlfunc.
strncatNot implemented. strncat() is C-specific, use .= instead, see perlop.
strncmpNot implemented. strncmp() is C-specific, use eq instead, see perlop.
strncpyNot implemented. strncpy() is C-specific, use = instead, see perlop.
strpbrkNot implemented. strpbrk() is C-specific, use regular expressions instead, see perlre.
strrchrNot implemented. strrchr() is C-specific, see "rindex" in perlfunc instead.
strspnNot implemented. strspn() is C-specific, use regular expressions instead, see perlre.
strstrThis is identical to Perl's builtin index() function, see "index" in perlfunc.
strtodString to double translation. Returns the parsed number and the number of characters in the unparsed portion of the string. Truly POSIX-compliant systems set $! ($ERRNO) to indicate a translation error, so clear $! before calling strtod. However, non-POSIX systems may not check for overflow, and therefore will never set $!.
strtod respects any POSIX setlocale() LC_TIME settings, regardless of whether or not it is called from Perl code that is within the scope of use locale.
To parse a string $str as a floating point number use
$! = 0;
($num, $n_unparsed) = POSIX::strtod($str);
The second returned item and $! can be used to check for valid input:
if (($str eq '') || ($n_unparsed != 0) || $!) {
die "Non-numeric input $str" . ($! ? ": $!\n" : "\n");
}
When called in a scalar context strtod returns the parsed number.
strtokNot implemented. strtok() is C-specific, use regular expressions instead, see perlre, or "split" in perlfunc.
strtolString to (long) integer translation. Returns the parsed number and the number of characters in the unparsed portion of the string. Truly POSIX-compliant systems set $! ($ERRNO) to indicate a translation error, so clear $! before calling strtol. However, non-POSIX systems may not check for overflow, and therefore will never set $!.
strtol should respect any POSIX setlocale() settings.
To parse a string $str as a number in some base $base use
$! = 0;
($num, $n_unparsed) = POSIX::strtol($str, $base);
The base should be zero or between 2 and 36, inclusive. When the base is zero or omitted strtol will use the string itself to determine the base: a leading "0x" or "0X" means hexadecimal; a leading "0" means octal; any other leading characters mean decimal. Thus, "1234" is parsed as a decimal number, "01234" as an octal number, and "0x1234" as a hexadecimal number.
The second returned item and $! can be used to check for valid input:
if (($str eq '') || ($n_unparsed != 0) || !$!) {
die "Non-numeric input $str" . $! ? ": $!\n" : "\n";
}
When called in a scalar context strtol returns the parsed number.
strtoldLike "strtod" but for long doubles. Defined only if the system supports long doubles.
strtoulString to unsigned (long) integer translation. strtoul() is identical to strtol() except that strtoul() only parses unsigned integers. See "strtol" for details.
Note: Some vendors supply strtod() and strtol() but not strtoul(). Other vendors that do supply strtoul() parse "-1" as a valid value.
strxfrmString transformation. Returns the transformed string.
$dst = POSIX::strxfrm( $src );
Used in conjunction with the strcoll() function, see "strcoll".
Not really needed since Perl can do this transparently, see perllocale.
sysconfRetrieves values of system configurable variables.
The following will get the machine's clock speed.
$clock_ticks = POSIX::sysconf( &POSIX::_SC_CLK_TCK );
Returns undef on failure.
systemThis is identical to Perl's builtin system() function, see "system" in perlfunc.
tanThis is identical to the C function tan(), returning the tangent of the numerical argument. See also Math::Trig.
tanhThis is identical to the C function tanh(), returning the hyperbolic tangent of the numerical argument. See also Math::Trig.
tcdrainThis is similar to the C function tcdrain() for draining the output queue of its argument stream.
Returns undef on failure.
tcflowThis is similar to the C function tcflow() for controlling the flow of its argument stream.
Returns undef on failure.
tcflushThis is similar to the C function tcflush() for flushing the I/O buffers of its argument stream.
Returns undef on failure.
tcgetpgrpThis is identical to the C function tcgetpgrp() for returning the process group identifier of the foreground process group of the controlling terminal.
tcsendbreakThis is similar to the C function tcsendbreak() for sending a break on its argument stream.
Returns undef on failure.
tcsetpgrpThis is similar to the C function tcsetpgrp() for setting the process group identifier of the foreground process group of the controlling terminal.
Returns undef on failure.
tgammaThe Gamma function [C99].
See also "lgamma".
timeThis is identical to Perl's builtin time() function for returning the number of seconds since the epoch (whatever it is for the system), see "time" in perlfunc.
timesThe times() function returns elapsed realtime since some point in the past (such as system startup), user and system times for this process, and user and system times used by child processes. All times are returned in clock ticks.
($realtime, $user, $system, $cuser, $csystem)
= POSIX::times();
Note: Perl's builtin times() function returns four values, measured in seconds.
tmpfileNot implemented. Use method IO::File::new_tmpfile() instead, or see File::Temp.
tmpnamReturns a name for a temporary file.
$tmpfile = POSIX::tmpnam();
For security reasons, which are probably detailed in your system's documentation for the C library tmpnam() function, this interface should not be used; instead see File::Temp.
tolowerThis is identical to the C function, except that it can apply to a single character or to a whole string, and currently operates as if the locale always is "C". Consider using the lc() function, see "lc" in perlfunc, see "lc" in perlfunc, or the equivalent \L operator inside doublequotish strings.
toupperThis is similar to the C function, except that it can apply to a single character or to a whole string, and currently operates as if the locale always is "C". Consider using the uc() function, see "uc" in perlfunc, or the equivalent \U operator inside doublequotish strings.
truncReturns the integer toward zero from the argument [C99].
ttynameThis is identical to the C function ttyname() for returning the name of the current terminal.
tznameRetrieves the time conversion information from the tzname variable.
POSIX::tzset();
($std, $dst) = POSIX::tzname();
tzsetThis is identical to the C function tzset() for setting the current timezone based on the environment variable TZ, to be used by ctime(), localtime(), mktime(), and strftime() functions.
umaskThis is identical to Perl's builtin umask() function for setting (and querying) the file creation permission mask, see "umask" in perlfunc.
unameGet name of current operating system.
($sysname, $nodename, $release, $version, $machine)
= POSIX::uname();
Note that the actual meanings of the various fields are not that well standardized, do not expect any great portability. The $sysname might be the name of the operating system, the $nodename might be the name of the host, the $release might be the (major) release number of the operating system, the $version might be the (minor) release number of the operating system, and the $machine might be a hardware identifier. Maybe.
ungetcNot implemented. Use method IO::Handle::ungetc() instead.
unlinkThis is identical to Perl's builtin unlink() function for removing files, see "unlink" in perlfunc.
utimeThis is identical to Perl's builtin utime() function for changing the time stamps of files and directories, see "utime" in perlfunc.
vfprintfNot implemented. vfprintf() is C-specific, see "printf" in perlfunc instead.
vprintfNot implemented. vprintf() is C-specific, see "printf" in perlfunc instead.
vsprintfNot implemented. vsprintf() is C-specific, see "sprintf" in perlfunc instead.
waitThis is identical to Perl's builtin wait() function, see "wait" in perlfunc.
waitpidWait for a child process to change state. This is identical to Perl's builtin waitpid() function, see "waitpid" in perlfunc.
$pid = POSIX::waitpid( -1, POSIX::WNOHANG );
print "status = ", ($? / 256), "\n";
wcstombsThis is identical to the C function wcstombs().
See "mblen".
wctombThis is identical to the C function wctomb().
See "mblen".
writeWrite to a file. This uses file descriptors such as those obtained by calling POSIX::open.
$fd = POSIX::open( "foo", &POSIX::O_WRONLY );
$buf = "hello";
$bytes = POSIX::write( $fd, $buf, 5 );
Returns undef on failure.
See also "syswrite" in perlfunc.
POSIX::SigActionnewCreates a new POSIX::SigAction object which corresponds to the C struct sigaction. This object will be destroyed automatically when it is no longer needed. The first parameter is the handler, a sub reference. The second parameter is a POSIX::SigSet object, it defaults to the empty set. The third parameter contains the sa_flags, it defaults to 0.
$sigset = POSIX::SigSet->new(SIGINT, SIGQUIT);
$sigaction = POSIX::SigAction->new(
\&handler, $sigset, &POSIX::SA_NOCLDSTOP
);
This POSIX::SigAction object is intended for use with the POSIX::sigaction() function.
handlermaskflagsaccessor functions to get/set the values of a SigAction object.
$sigset = $sigaction->mask;
$sigaction->flags(&POSIX::SA_RESTART);
safeaccessor function for the "safe signals" flag of a SigAction object; see perlipc for general information on safe (a.k.a. "deferred") signals. If you wish to handle a signal safely, use this accessor to set the "safe" flag in the POSIX::SigAction object:
$sigaction->safe(1);
You may also examine the "safe" flag on the output action object which is filled in when given as the third parameter to POSIX::sigaction():
sigaction(SIGINT, $new_action, $old_action);
if ($old_action->safe) {
# previous SIGINT handler used safe signals
}
POSIX::SigRt%SIGRTA hash of the POSIX realtime signal handlers. It is an extension of the standard %SIG, the $POSIX::SIGRT{SIGRTMIN} is roughly equivalent to $SIG{SIGRTMIN}, but the right POSIX moves (see below) are made with the POSIX::SigSet and POSIX::sigaction instead of accessing the %SIG.
You can set the %POSIX::SIGRT elements to set the POSIX realtime signal handlers, use delete and exists on the elements, and use scalar on the %POSIX::SIGRT to find out how many POSIX realtime signals there are available (SIGRTMAX - SIGRTMIN + 1, the SIGRTMAX is a valid POSIX realtime signal).
Setting the %SIGRT elements is equivalent to calling this:
sub new {
my ($rtsig, $handler, $flags) = @_;
my $sigset = POSIX::SigSet($rtsig);
my $sigact = POSIX::SigAction->new($handler,$sigset,$flags);
sigaction($rtsig, $sigact);
}
The flags default to zero, if you want something different you can either use local on $POSIX::SigRt::SIGACTION_FLAGS, or you can derive from POSIX::SigRt and define your own new() (the tied hash STORE method of the %SIGRT calls new($rtsig, $handler, $SIGACTION_FLAGS), where the $rtsig ranges from zero to SIGRTMAX - SIGRTMIN + 1).
Just as with any signal, you can use sigaction($rtsig, undef, $oa) to retrieve the installed signal handler (or, rather, the signal action).
NOTE: whether POSIX realtime signals really work in your system, or whether Perl has been compiled so that it works with them, is outside of this discussion.
SIGRTMINReturn the minimum POSIX realtime signal number available, or undef if no POSIX realtime signals are available.
SIGRTMAXReturn the maximum POSIX realtime signal number available, or undef if no POSIX realtime signals are available.
POSIX::SigSetnewCreate a new SigSet object. This object will be destroyed automatically when it is no longer needed. Arguments may be supplied to initialize the set.
Create an empty set.
$sigset = POSIX::SigSet->new;
Create a set with SIGUSR1.
$sigset = POSIX::SigSet->new( &POSIX::SIGUSR1 );
addsetAdd a signal to a SigSet object.
$sigset->addset( &POSIX::SIGUSR2 );
Returns undef on failure.
delsetRemove a signal from the SigSet object.
$sigset->delset( &POSIX::SIGUSR2 );
Returns undef on failure.
emptysetInitialize the SigSet object to be empty.
$sigset->emptyset();
Returns undef on failure.
fillsetInitialize the SigSet object to include all signals.
$sigset->fillset();
Returns undef on failure.
ismemberTests the SigSet object to see if it contains a specific signal.
if( $sigset->ismember( &POSIX::SIGUSR1 ) ){
print "contains SIGUSR1\n";
}
POSIX::TermiosnewCreate a new Termios object. This object will be destroyed automatically when it is no longer needed. A Termios object corresponds to the termios C struct. new() mallocs a new one, getattr() fills it from a file descriptor, and setattr() sets a file descriptor's parameters to match Termios' contents.
$termios = POSIX::Termios->new;
getattrGet terminal control attributes.
Obtain the attributes for stdin.
$termios->getattr( 0 ) # Recommended for clarity.
$termios->getattr()
Obtain the attributes for stdout.
$termios->getattr( 1 )
Returns undef on failure.
getccRetrieve a value from the c_cc field of a termios object. The c_cc field is an array so an index must be specified.
$c_cc[1] = $termios->getcc(1);
getcflagRetrieve the c_cflag field of a termios object.
$c_cflag = $termios->getcflag;
getiflagRetrieve the c_iflag field of a termios object.
$c_iflag = $termios->getiflag;
getispeedRetrieve the input baud rate.
$ispeed = $termios->getispeed;
getlflagRetrieve the c_lflag field of a termios object.
$c_lflag = $termios->getlflag;
getoflagRetrieve the c_oflag field of a termios object.
$c_oflag = $termios->getoflag;
getospeedRetrieve the output baud rate.
$ospeed = $termios->getospeed;
setattrSet terminal control attributes.
Set attributes immediately for stdout.
$termios->setattr( 1, &POSIX::TCSANOW );
Returns undef on failure.
setccSet a value in the c_cc field of a termios object. The c_cc field is an array so an index must be specified.
$termios->setcc( &POSIX::VEOF, 1 );
setcflagSet the c_cflag field of a termios object.
$termios->setcflag( $c_cflag | &POSIX::CLOCAL );
setiflagSet the c_iflag field of a termios object.
$termios->setiflag( $c_iflag | &POSIX::BRKINT );
setispeedSet the input baud rate.
$termios->setispeed( &POSIX::B9600 );
Returns undef on failure.
setlflagSet the c_lflag field of a termios object.
$termios->setlflag( $c_lflag | &POSIX::ECHO );
setoflagSet the c_oflag field of a termios object.
$termios->setoflag( $c_oflag | &POSIX::OPOST );
setospeedSet the output baud rate.
$termios->setospeed( &POSIX::B9600 );
Returns undef on failure.
B38400 B75 B200 B134 B300 B1800 B150 B0 B19200 B1200 B9600 B600 B4800 B50 B2400 B110
TCSADRAIN TCSANOW TCOON TCIOFLUSH TCOFLUSH TCION TCIFLUSH TCSAFLUSH TCIOFF TCOOFF
c_cc field valuesVEOF VEOL VERASE VINTR VKILL VQUIT VSUSP VSTART VSTOP VMIN VTIME NCCS
c_cflag field valuesCLOCAL CREAD CSIZE CS5 CS6 CS7 CS8 CSTOPB HUPCL PARENB PARODD
c_iflag field valuesBRKINT ICRNL IGNBRK IGNCR IGNPAR INLCR INPCK ISTRIP IXOFF IXON PARMRK
c_lflag field valuesECHO ECHOE ECHOK ECHONL ICANON IEXTEN ISIG NOFLSH TOSTOP
c_oflag field valuesOPOST
_PC_CHOWN_RESTRICTED _PC_LINK_MAX _PC_MAX_CANON _PC_MAX_INPUT _PC_NAME_MAX _PC_NO_TRUNC _PC_PATH_MAX _PC_PIPE_BUF _PC_VDISABLE
_POSIX_ARG_MAX _POSIX_CHILD_MAX _POSIX_CHOWN_RESTRICTED _POSIX_JOB_CONTROL _POSIX_LINK_MAX _POSIX_MAX_CANON _POSIX_MAX_INPUT _POSIX_NAME_MAX _POSIX_NGROUPS_MAX _POSIX_NO_TRUNC _POSIX_OPEN_MAX _POSIX_PATH_MAX _POSIX_PIPE_BUF _POSIX_SAVED_IDS _POSIX_SSIZE_MAX _POSIX_STREAM_MAX _POSIX_TZNAME_MAX _POSIX_VDISABLE _POSIX_VERSION
_SC_ARG_MAX _SC_CHILD_MAX _SC_CLK_TCK _SC_JOB_CONTROL _SC_NGROUPS_MAX _SC_OPEN_MAX _SC_PAGESIZE _SC_SAVED_IDS _SC_STREAM_MAX _SC_TZNAME_MAX _SC_VERSION
E2BIG EACCES EADDRINUSE EADDRNOTAVAIL EAFNOSUPPORT EAGAIN EALREADY EBADF EBADMSG EBUSY ECANCELED ECHILD ECONNABORTED ECONNREFUSED ECONNRESET EDEADLK EDESTADDRREQ EDOM EDQUOT EEXIST EFAULT EFBIG EHOSTDOWN EHOSTUNREACH EIDRM EILSEQ EINPROGRESS EINTR EINVAL EIO EISCONN EISDIR ELOOP EMFILE EMLINK EMSGSIZE ENAMETOOLONG ENETDOWN ENETRESET ENETUNREACH ENFILE ENOBUFS ENODATA ENODEV ENOENT ENOEXEC ENOLCK ENOLINK ENOMEM ENOMSG ENOPROTOOPT ENOSPC ENOSR ENOSTR ENOSYS ENOTBLK ENOTCONN ENOTDIR ENOTEMPTY ENOTRECOVERABLE ENOTSOCK ENOTSUP ENOTTY ENXIO EOPNOTSUPP EOTHER EOVERFLOW EOWNERDEAD EPERM EPFNOSUPPORT EPIPE EPROCLIM EPROTO EPROTONOSUPPORT EPROTOTYPE ERANGE EREMOTE ERESTART EROFS ESHUTDOWN ESOCKTNOSUPPORT ESPIPE ESRCH ESTALE ETIME ETIMEDOUT ETOOMANYREFS ETXTBSY EUSERS EWOULDBLOCK EXDEV
FD_CLOEXEC F_DUPFD F_GETFD F_GETFL F_GETLK F_OK F_RDLCK F_SETFD F_SETFL F_SETLK F_SETLKW F_UNLCK F_WRLCK O_ACCMODE O_APPEND O_CREAT O_EXCL O_NOCTTY O_NONBLOCK O_RDONLY O_RDWR O_TRUNC O_WRONLY
DBL_DIG DBL_EPSILON DBL_MANT_DIG DBL_MAX DBL_MAX_10_EXP DBL_MAX_EXP DBL_MIN DBL_MIN_10_EXP DBL_MIN_EXP FLT_DIG FLT_EPSILON FLT_MANT_DIG FLT_MAX FLT_MAX_10_EXP FLT_MAX_EXP FLT_MIN FLT_MIN_10_EXP FLT_MIN_EXP FLT_RADIX FLT_ROUNDS LDBL_DIG LDBL_EPSILON LDBL_MANT_DIG LDBL_MAX LDBL_MAX_10_EXP LDBL_MAX_EXP LDBL_MIN LDBL_MIN_10_EXP LDBL_MIN_EXP
FE_DOWNWARD FE_TONEAREST FE_TOWARDZERO FE_UPWARD on systems that support them.
ARG_MAX CHAR_BIT CHAR_MAX CHAR_MIN CHILD_MAX INT_MAX INT_MIN LINK_MAX LONG_MAX LONG_MIN MAX_CANON MAX_INPUT MB_LEN_MAX NAME_MAX NGROUPS_MAX OPEN_MAX PATH_MAX PIPE_BUF SCHAR_MAX SCHAR_MIN SHRT_MAX SHRT_MIN SSIZE_MAX STREAM_MAX TZNAME_MAX UCHAR_MAX UINT_MAX ULONG_MAX USHRT_MAX
LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME LC_MESSAGES on systems that support them.
HUGE_VAL
FP_ILOGB0 FP_ILOGBNAN FP_INFINITE FP_NAN FP_NORMAL FP_SUBNORMAL FP_ZERO INFINITY NAN Inf NaN M_1_PI M_2_PI M_2_SQRTPI M_E M_LN10 M_LN2 M_LOG10E M_LOG2E M_PI M_PI_2 M_PI_4 M_SQRT1_2 M_SQRT2 on systems with C99 support.
SA_NOCLDSTOP SA_NOCLDWAIT SA_NODEFER SA_ONSTACK SA_RESETHAND SA_RESTART SA_SIGINFO SIGABRT SIGALRM SIGCHLD SIGCONT SIGFPE SIGHUP SIGILL SIGINT SIGKILL SIGPIPE SIGQUIT SIGSEGV SIGSTOP SIGTERM SIGTSTP SIGTTIN SIGTTOU SIGUSR1 SIGUSR2 SIG_BLOCK SIG_DFL SIG_ERR SIG_IGN SIG_SETMASK SIG_UNBLOCK ILL_ILLOPC ILL_ILLOPN ILL_ILLADR ILL_ILLTRP ILL_PRVOPC ILL_PRVREG ILL_COPROC ILL_BADSTK FPE_INTDIV FPE_INTOVF FPE_FLTDIV FPE_FLTOVF FPE_FLTUND FPE_FLTRES FPE_FLTINV FPE_FLTSUB SEGV_MAPERR SEGV_ACCERR BUS_ADRALN BUS_ADRERR BUS_OBJERR TRAP_BRKPT TRAP_TRACE CLD_EXITED CLD_KILLED CLD_DUMPED CLD_TRAPPED CLD_STOPPED CLD_CONTINUED POLL_IN POLL_OUT POLL_MSG POLL_ERR POLL_PRI POLL_HUP SI_USER SI_QUEUE SI_TIMER SI_ASYNCIO SI_MESGQ
S_IRGRP S_IROTH S_IRUSR S_IRWXG S_IRWXO S_IRWXU S_ISGID S_ISUID S_IWGRP S_IWOTH S_IWUSR S_IXGRP S_IXOTH S_IXUSR
S_ISBLK S_ISCHR S_ISDIR S_ISFIFO S_ISREG
EXIT_FAILURE EXIT_SUCCESS MB_CUR_MAX RAND_MAX
BUFSIZ EOF FILENAME_MAX L_ctermid L_cuserid L_tmpname TMP_MAX
CLK_TCK CLOCKS_PER_SEC
R_OK SEEK_CUR SEEK_END SEEK_SET STDIN_FILENO STDOUT_FILENO STDERR_FILENO W_OK X_OK
WNOHANG WUNTRACED
WIFEXITED WEXITSTATUS WIFSIGNALED WTERMSIG WIFSTOPPED WSTOPSIG
WIFEXITEDWIFEXITED(${^CHILD_ERROR_NATIVE}) returns true if the child process exited normally (exit() or by falling off the end of main())
WEXITSTATUSWEXITSTATUS(${^CHILD_ERROR_NATIVE}) returns the normal exit status of the child process (only meaningful if WIFEXITED(${^CHILD_ERROR_NATIVE}) is true)
WIFSIGNALEDWIFSIGNALED(${^CHILD_ERROR_NATIVE}) returns true if the child process terminated because of a signal
WTERMSIGWTERMSIG(${^CHILD_ERROR_NATIVE}) returns the signal the child process terminated for (only meaningful if WIFSIGNALED(${^CHILD_ERROR_NATIVE}) is true)
WIFSTOPPEDWIFSTOPPED(${^CHILD_ERROR_NATIVE}) returns true if the child process is currently stopped (can happen only if you specified the WUNTRACED flag to waitpid())
WSTOPSIGWSTOPSIG(${^CHILD_ERROR_NATIVE}) returns the signal the child process was stopped for (only meaningful if WIFSTOPPED(${^CHILD_ERROR_NATIVE}) is true)
(Windows only.)
WSAEINTR WSAEBADF WSAEACCES WSAEFAULT WSAEINVAL WSAEMFILE WSAEWOULDBLOCK WSAEINPROGRESS WSAEALREADY WSAENOTSOCK WSAEDESTADDRREQ WSAEMSGSIZE WSAEPROTOTYPE WSAENOPROTOOPT WSAEPROTONOSUPPORT WSAESOCKTNOSUPPORT WSAEOPNOTSUPP WSAEPFNOSUPPORT WSAEAFNOSUPPORT WSAEADDRINUSE WSAEADDRNOTAVAIL WSAENETDOWN WSAENETUNREACH WSAENETRESET WSAECONNABORTED WSAECONNRESET WSAENOBUFS WSAEISCONN WSAENOTCONN WSAESHUTDOWN WSAETOOMANYREFS WSAETIMEDOUT WSAECONNREFUSED WSAELOOP WSAENAMETOOLONG WSAEHOSTDOWN WSAEHOSTUNREACH WSAENOTEMPTY WSAEPROCLIM WSAEUSERS WSAEDQUOT WSAESTALE WSAEREMOTE WSAEDISCON WSAENOMORE WSAECANCELLED WSAEINVALIDPROCTABLE WSAEINVALIDPROVIDER WSAEPROVIDERFAILEDINIT WSAEREFUSED