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 L<perlfunc> for functions which are noted as being
-identical to Perl's builtin functions.
+identical or almost 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,
=item C<abs>
-This is identical to Perl's builtin C<abs()> function, returning
-the absolute value of its numerical argument.
+This is identical to Perl's builtin C<abs()> function, returning the absolute
+value of its numerical argument (except that C<POSIX::abs()> must be provided
+an explicit value (rather than relying on an implicit C<$_>):
+
+ $absolute_value = POSIX::abs(42); # good
+
+ $absolute_value = POSIX::abs(); # throws exception
=item C<access>
This is identical to the C function C<acosh()>, returning the
hyperbolic arcus cosine of its numerical argument [C99]. See also
-L<Math::Trig>.
+L<Math::Trig>. Added in Perl v5.22.
=item C<alarm>
-This is identical to Perl's builtin C<alarm()> function,
-either for arming or disarming the C<SIGARLM> timer.
+This is identical to Perl's builtin C<alarm()> function, either for arming or
+disarming the C<SIGARLM> timer, except that C<POSIX::alarm()> must be provided
+an explicit value (rather than relying on an implicit C<$_>):
+
+ POSIX::alarm(3) # good
+
+ POSIX::alarm() # throws exception
=item C<asctime>
1900-based: 2001 equals C<101>. C<$wday> and C<$yday> default to zero
(and are usually ignored anyway), and C<$isdst> defaults to -1.
+Note the result is always in English. Use C<L</strftime>> instead to
+get a result suitable for the current locale. That function's C<%c>
+format yields the locale's preferred representation.
+
=item C<asin>
This is identical to the C function C<asin()>, returning
This is identical to the C function C<asinh()>, returning the
hyperbolic arcus sine of its numerical argument [C99]. See also
-L<Math::Trig>.
+L<Math::Trig>. Added in Perl v5.22.
=item C<assert>
This is identical to the C function C<atanh()>, returning the
hyperbolic arcus tangent of its numerical argument [C99]. See also
-L<Math::Trig>.
+L<Math::Trig>. Added in Perl v5.22.
=item C<atan2>
=item C<cbrt>
-The cube root [C99].
+The cube root [C99]. Added in Perl v5.22.
=item C<ceil>
=item C<chdir>
-This is identical to Perl's builtin C<chdir()> function, allowing
-one to change the working (default) directory, see L<perlfunc/chdir>.
+This is identical to Perl's builtin C<chdir()> function, allowing one to
+change the working (default) directory -- see L<perlfunc/chdir> -- with the
+exception that C<POSIX::chdir()> must be provided an explicit value (rather
+than relying on an implicit C<$_>):
+
+ $rv = POSIX::chdir('path/to/dir'); # good
+
+ $rv = POSIX::chdir(); # throws exception
=item C<chmod>
This is identical to Perl's builtin C<chmod()> function, allowing
-one to change file and directory permissions, see L<perlfunc/chmod>.
+one to change file and directory permissions -- see L<perlfunc/chmod> -- with
+the exception that C<POSIX::chmod()> can only change one file at a time
+(rather than a list of files):
+
+ $c = chmod 0664, $file1, $file2; # good
+
+ $c = POSIX::chmod 0664, $file1; # throws exception
+
+ $c = POSIX::chmod 0664, $file1, $file2; # throws exception
+
+As with the built-in C<chmod()>, C<$file> may be a filename or a file
+handle.
=item C<chown>
=item C<copysign>
-Returns C<x> but with the sign of C<y> [C99].
+Returns C<x> but with the sign of C<y> [C99]. Added in Perl v5.22.
$x_with_sign_of_y = POSIX::copysign($x, $y);
This is identical to the C function C<ctime()> and equivalent
to C<asctime(localtime(...))>, see L</asctime> and L</localtime>.
-=item C<cuserid>
+=item C<cuserid> [POSIX.1-1988]
Get the login name of the owner of the current process.
$name = POSIX::cuserid();
+Note: this function has not been specified by POSIX since 1990 and is included
+only for backwards compatibility. New code should use L<C<getlogin()>|perlfunc/getlogin> instead.
+
=item C<difftime>
This is identical to the C function C<difftime()>, for returning
=item C<erf>
-The error function [C99].
+The error function [C99]. Added in Perl v5.22.
=item C<erfc>
-The complementary error function [C99].
+The complementary error function [C99]. Added in Perl v5.22.
=item C<errno>
=item C<expm1>
Equivalent to C<exp(x) - 1>, but more precise for small argument values [C99].
+Added in Perl v5.22.
See also L</log1p>.
=item C<fdim>
"Positive difference", S<C<x - y>> if S<C<x E<gt> y>>, zero otherwise [C99].
+Added in Perl v5.22.
=item C<fegetround>
Returns the current floating point rounding mode, one of
- FE_TONEAREST FE_TOWARDZERO FE_UPWARD FE_UPWARD
+ FE_TONEAREST FE_TOWARDZERO FE_UPWARD FE_DOWNWARD
C<FE_TONEAREST> is like L</round>, C<FE_TOWARDZERO> is like L</trunc> [C99].
+Added in Perl v5.22.
=item C<fesetround>
-Sets the floating point rounding mode, see L</fegetround> [C99].
+Sets the floating point rounding mode, see L</fegetround> [C99]. Added in
+Perl v5.22.
=item C<fma>
"Fused multiply-add", S<C<x * y + z>>, possibly faster (and less lossy)
-than the explicit two operations [C99].
+than the explicit two operations [C99]. Added in Perl v5.22.
my $fused = POSIX::fma($x, $y, $z);
=item C<fmax>
Maximum of C<x> and C<y>, except when either is C<NaN>, returns the other [C99].
+Added in Perl v5.22.
my $min = POSIX::fmax($x, $y);
=item C<fmin>
Minimum of C<x> and C<y>, except when either is C<NaN>, returns the other [C99].
+Added in Perl v5.22.
my $min = POSIX::fmin($x, $y);
or negative infinity, C<FP_NAN> is not-a-number. C<FP_SUBNORMAL>
means subnormal numbers (also known as denormals), very small numbers
with low precision. C<FP_ZERO> is zero. C<FP_NORMAL> is all the rest.
+Added in Perl v5.22.
=item C<fprintf>
use POSIX ':nan_payload';
getpayload($var)
-Returns the C<NaN> payload.
+Returns the C<NaN> payload. Added in Perl v5.24.
Note the API instability warning in L</setpayload>.
=item C<hypot>
Equivalent to C<S<sqrt(x * x + y * y)>> except more stable on very large
-or very small arguments [C99].
+or very small arguments [C99]. Added in Perl v5.22.
=item C<ilogb>
-Integer binary logarithm [C99]
+Integer binary logarithm [C99]. Added in Perl v5.22.
For example C<ilogb(20)> is 4, as an integer.
=item C<isalnum>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:alnum:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
=item C<isalpha>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:alpha:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
=item C<iscntrl>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:cntrl:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
=item C<isdigit>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:digit:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
=item C<isfinite>
Returns true if the argument is a finite number (that is, not an
-infinity, or the not-a-number) [C99].
+infinity, or the not-a-number) [C99]. Added in Perl v5.22.
See also L</isinf>, L</isnan>, and L</fpclassify>.
=item C<isgraph>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:graph:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
(Also C<isgreaterequal>, C<isless>, C<islessequal>, C<islessgreater>,
C<isunordered>)
-Floating point comparisons which handle the C<NaN> [C99].
+Floating point comparisons which handle the C<NaN> [C99]. Added in Perl
+v5.22.
=item C<isinf>
Returns true if the argument is an infinity (positive or negative) [C99].
+Added in Perl v5.22.
See also L</Inf>, L</isnan>, L</isfinite>, and L</fpclassify>.
=item C<islower>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:lower:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
=item C<isnan>
-Returns true if the argument is C<NaN> (not-a-number) [C99].
+Returns true if the argument is C<NaN> (not-a-number) [C99]. Added in
+Perl v5.22.
Note that you cannot test for "C<NaN>-ness" with
=item C<isnormal>
Returns true if the argument is normal (that is, not a subnormal/denormal,
-and not an infinity, or a not-a-number) [C99].
+and not an infinity, or a not-a-number) [C99]. Added in Perl v5.22.
See also L</isfinite>, and L</fpclassify>.
=item C<isprint>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:print:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
=item C<ispunct>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:punct:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
use POSIX ':nan_payload';
issignaling($var, $payload)
-Return true if the argument is a I<signaling> NaN.
+Return true if the argument is a I<signaling> NaN. Added in Perl v5.24.
Note the API instability warning in L</setpayload>.
=item C<isspace>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:space:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
=item C<isupper>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:upper:]]+ $ /x>>, which you should convert
to use instead. See L<perlrecharclass/POSIX Character Classes>.
=item C<isxdigit>
-This function has been removed as of v5.24. It was very similar to
+This function has been removed as of Perl v5.24. It was very similar to
matching against S<C<qr/ ^ [[:xdigit:]]+ $ /x>>, which you should
convert to use instead. See L<perlrecharclass/POSIX Character Classes>.
=item C<lgamma>
-The logarithm of the Gamma function [C99].
+The logarithm of the Gamma function [C99]. Added in Perl v5.22.
See also L</tgamma>.
=item C<log1p>
Equivalent to S<C<log(1 + x)>>, but more stable results for small argument
-values [C99].
+values [C99]. Added in Perl v5.22.
=item C<log2>
-Logarithm base two [C99].
+Logarithm base two [C99]. Added in Perl v5.22.
See also L</expm1>.
=item C<logb>
-Integer binary logarithm [C99].
+Integer binary logarithm [C99]. Added in Perl v5.22.
For example C<logb(20)> is 4, as a floating point number.
=item C<localeconv>
Get numeric formatting information. Returns a reference to a hash
-containing the current underlying locale's formatting values. Users of this function
-should also read L<perllocale>, which provides a comprehensive
-discussion of Perl locale handling, including
+containing the formatting values of the locale that currently underlies
+the program, regardless of whether or not it is called from within the
+scope of a S<C<use locale>>. Users of this function should also read
+L<perllocale>, which provides a comprehensive discussion of Perl locale
+handling, including
L<a section devoted to this function|perllocale/The localeconv function>.
+Prior to Perl 5.28, or when operating in a non thread-safe environment,
+it should not be used in a threaded application unless it's certain that
+the underlying locale is C or POSIX. This is because it otherwise
+changes the locale, which globally affects all threads simultaneously.
+Windows platforms starting with Visual Studio 2005 are mostly
+thread-safe, but use of this function in those prior to Visual Studio
+2015 can interfere with a thread that has called
+L<perlapi/switch_to_global_locale>.
Here is how to query the database for the B<de> (Deutsch or German) locale.
=item C<localtime>
This is identical to Perl's builtin C<localtime()> function for
-converting seconds since the epoch to a date see L<perlfunc/localtime>.
+converting seconds since the epoch to a date see L<perlfunc/localtime> except
+that C<POSIX::localtime()> must be provided an explicit value (rather than
+relying on an implicit C<$_>):
+
+ @localtime = POSIX::localtime(time); # good
+
+ @localtime = localtime(); # good
+
+ @localtime = POSIX::localtime(); # throws exception
=item C<log>
Depending on the current floating point rounding mode, rounds the
argument either toward nearest (like L</round>), toward zero (like
L</trunc>), downward (toward negative infinity), or upward (toward
-positive infinity) [C99].
+positive infinity) [C99]. Added in Perl v5.22.
For the rounding mode, see L</fegetround>.
=item C<lround>
-Like L</round>, but as integer, as opposed to floating point [C99].
+Like L</round>, but as integer, as opposed to floating point [C99]. Added
+in Perl v5.22.
See also L</ceil>, L</floor>, L</trunc>.
Owing to an oversight, this is not currently exported by default, or as part of
the C<:math_h_c99> export tag; importing it must therefore be done by explicit
-name. This will be changed in Perl 5.26.
+name.
=item C<malloc>
=item C<mblen>
-This is identical to the C function C<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 L<perluniintro>.
-
-=item C<mbstowcs>
-
-This is identical to the C function C<mbstowcs()>.
-
-See L</mblen>.
+This is the same as the C function C<mblen()> on unthreaded perls. On
+threaded perls, it transparently (almost) substitutes the more
+thread-safe L<C<mbrlen>(3)>, if available, instead of C<mblen>.
+
+Core Perl does not have any support for wide and multibyte locales,
+except Unicode UTF-8 locales. This function, in conjunction with
+L</mbtowc> and L</wctomb> may be used to roll your own decoding/encoding
+of other types of multi-byte locales.
+
+Use C<undef> as the first parameter to this function to get the effect
+of passing NULL as the first parameter to C<mblen>. This resets any
+shift state to its initial value. The return value is undefined if
+C<mbrlen> was substituted, so you should never rely on it.
+
+When the first parameter is a scalar containing a value that either is a
+PV string or can be forced into one, the return value is the number of
+bytes occupied by the first character of that string; or 0 if that first
+character is the wide NUL character; or negative if there is an error.
+This is based on the locale that currently underlies the program,
+regardless of whether or not the function is called from Perl code that
+is within the scope of S<C<use locale>>. Perl makes no attempt at
+hiding from your code any differences in the C<errno> setting between
+C<mblen> and C<mbrlen>. It does set C<errno> to 0 before calling them.
+
+The optional second parameter is ignored if it is larger than the
+actual length of the first parameter string.
=item C<mbtowc>
-This is identical to the C function C<mbtowc()>.
-
-See L</mblen>.
+This is the same as the C function C<mbtowc()> on unthreaded perls. On
+threaded perls, it transparently (almost) substitutes the more
+thread-safe L<C<mbrtowc>(3)>, if available, instead of C<mbtowc>.
+
+Core Perl does not have any support for wide and multibyte locales,
+except Unicode UTF-8 locales. This function, in conjunction with
+L</mblen> and L</wctomb> may be used to roll your own decoding/encoding
+of other types of multi-byte locales.
+
+The first parameter is a scalar into which, upon success, the wide
+character represented by the multi-byte string contained in the second
+parameter is stored. The optional third parameter is ignored if it is
+larger than the actual length of the second parameter string.
+
+Use C<undef> as the second parameter to this function to get the effect
+of passing NULL as the second parameter to C<mbtowc>. This resets any
+shift state to its initial value. The return value is undefined if
+C<mbrtowc> was substituted, so you should never rely on it.
+
+When the second parameter is a scalar containing a value that either is
+a PV string or can be forced into one, the return value is the number of
+bytes occupied by the first character of that string; or 0 if that first
+character is the wide NUL character; or negative if there is an error.
+This is based on the locale that currently underlies the program,
+regardless of whether or not the function is called from Perl code that
+is within the scope of S<C<use locale>>. Perl makes no attempt at
+hiding from your code any differences in the C<errno> setting between
+C<mbtowc> and C<mbrtowc>. It does set C<errno> to 0 before calling
+them.
=item C<memchr>
my $nan = nan();
-Returns C<NaN>, not-a-number [C99].
+Returns C<NaN>, not-a-number [C99]. Added in Perl v5.22.
The returned NaN is always a I<quiet> NaN, as opposed to I<signaling>.
=item C<nearbyint>
Returns the nearest integer to the argument, according to the current
-rounding mode (see L</fegetround>) [C99].
+rounding mode (see L</fegetround>) [C99]. Added in Perl v5.22.
=item C<nextafter>
Returns the next representable floating point number after C<x> in the
-direction of C<y> [C99].
+direction of C<y> [C99]. Added in Perl v5.22.
my $nextafter = POSIX::nextafter($x, $y);
=item C<nexttoward>
Returns the next representable floating point number after C<x> in the
-direction of C<y> [C99].
+direction of C<y> [C99]. Added in Perl v5.22.
my $nexttoward = POSIX::nexttoward($x, $y);
=item C<remainder>
Given C<x> and C<y>, returns the value S<C<x - n*y>>, where C<n> is the integer
-closest to C<x>/C<y>. [C99]
+closest to C<x>/C<y> [C99]. Added in Perl v5.22.
my $remainder = POSIX::remainder($x, $y)
=item C<remove>
-This is identical to Perl's builtin C<unlink()> function
-for removing files, see L<perlfunc/unlink>.
+Deletes a name from the filesystem. Calls L<perlfunc/unlink> for
+files and L<perlfunc/rmdir> for directories.
=item C<remquo>
Like L</remainder> but also returns the low-order bits of the quotient (n)
-[C99]
+[C99]. Added in Perl v5.22.
(This is quite esoteric interface, mainly used to implement numerical
algorithms.)
=item C<round>
Returns the integer (but still as floating point) nearest to the
-argument [C99].
+argument [C99]. Added in Perl v5.22.
See also L</ceil>, L</floor>, L</lround>, L</modf>, and L</trunc>.
=item C<scalbn>
-Returns S<C<x * 2**y>> [C99].
+Returns S<C<x * 2**y>> [C99]. Added in Perl v5.22.
See also L</frexp> and L</ldexp>.
=item C<setlocale>
-WARNING! Do NOT use this function in a L<thread|threads>. The locale
-will change in all other threads at the same time, and should your
-thread get paused by the operating system, and another started, that
-thread will not have the locale it is expecting. On some platforms,
-there can be a race leading to segfaults if two threads call this
-function nearly simultaneously.
-
-Modifies and queries the program's underlying locale. Users of this
+WARNING! Prior to Perl 5.28 or on a system that does not support
+thread-safe locale operations, do NOT use this function in a
+L<thread|threads>. The locale will change in all other threads at the
+same time, and should your thread get paused by the operating system,
+and another started, that thread will not have the locale it is
+expecting. On some platforms, there can be a race leading to segfaults
+if two threads call this function nearly simultaneously. This warning
+does not apply on unthreaded builds, or on perls where
+C<${^SAFE_LOCALES}> exists and is non-zero; namely Perl 5.28 and later
+compiled to be locale-thread-safe.
+
+This function
+modifies and queries the program's underlying locale. Users of this
function should read L<perllocale>, whch provides a comprehensive
discussion of Perl locale handling, knowledge of which is necessary to
properly use this function. It contains
The discussion here is merely a summary reference for C<setlocale()>.
Note that Perl itself is almost entirely unaffected by the locale
except within the scope of S<C<"use locale">>. (Exceptions are listed
-in L<perllocale/Not within the scope of "use locale">.)
+in L<perllocale/Not within the scope of "use locale">, and
+locale-dependent functions within the POSIX module ARE always affected
+by the current locale.)
The following examples assume
use POSIX ':nan_payload';
setpayload($var, $payload);
-Sets the C<NaN> payload of var.
+Sets the C<NaN> payload of var. Added in Perl v5.24.
NOTE: the NaN payload APIs are based on the latest (as of June 2015)
proposed ISO C interfaces, but they are not yet a standard. Things
use POSIX ':nan_payload';
setpayloadsig($var, $payload);
-Like L</setpayload> but also makes the NaN I<signaling>.
+Like L</setpayload> but also makes the NaN I<signaling>. Added in Perl
+v5.24.
Depending on the platform the NaN may or may not behave differently.
otherwise the signal was sent by the kernel
The constants for specific C<code> values can be imported individually
-or using the C<:signal_h_si_code> tag.
+or using the C<:signal_h_si_code> tag, since Perl v5.24.
The following are also defined by POSIX/SUSv3, but unfortunately
not very widely implemented:
=item C<signbit>
Returns zero for positive arguments, non-zero for negative arguments [C99].
+Added in Perl v5.22.
=item C<sigpending>
error, so clear C<$!> before calling C<strtod>. However, non-POSIX systems
may not check for overflow, and therefore will never set C<$!>.
-C<strtod> respects any POSIX C<setlocale()> C<LC_TIME> settings,
+C<strtod> respects any POSIX C<setlocale()> C<LC_NUMERIC> settings,
regardless of whether or not it is called from Perl code that is within
-the scope of S<C<use locale>>.
+the scope of S<C<use locale>>. Prior to Perl 5.28, or when operating in
+a non thread-safe environment, it should not be used in a threaded
+application unless it's certain that the underlying locale is C
+or POSIX. This is because it otherwise changes the locale, which
+globally affects all threads simultaneously.
To parse a string C<$str> as a floating point number use
=item C<tgamma>
-The Gamma function [C99].
+The Gamma function [C99]. Added in Perl v5.22.
See also L</lgamma>.
For security reasons, which are probably detailed in your system's
documentation for the C library C<tmpnam()> function, this interface
-is no longer available; instead use L<File::Temp>.
+is no longer available since Perl v5.26; instead use L<File::Temp>.
=item C<tolower>
+This function has been removed as of Perl v5.26.
This 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 C<lc()> function, see L<perlfunc/lc>,
=item C<toupper>
+This function has been removed as of Perl v5.26.
This 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 C<uc()> function, see L<perlfunc/uc>,
=item C<trunc>
-Returns the integer toward zero from the argument [C99].
+Returns the integer toward zero from the argument [C99]. Added in Perl
+v5.22.
See also L</ceil>, L</floor>, and L</round>.
$pid = POSIX::waitpid( -1, POSIX::WNOHANG );
print "status = ", ($? / 256), "\n";
-=item C<wcstombs>
-
-This is identical to the C function C<wcstombs()>.
-
See L</mblen>.
=item C<wctomb>
-This is identical to the C function C<wctomb()>.
-
-See L</mblen>.
+This is the same as the C function C<wctomb()> on unthreaded perls. On
+threaded perls, it transparently (almost) substitutes the more
+thread-safe L<C<wcrtomb>(3)>, if available, instead of C<wctomb>.
+
+Core Perl does not have any support for wide and multibyte locales,
+except Unicode UTF-8 locales. This function, in conjunction with
+L</mblen> and L</mbtowc> may be used to roll your own decoding/encoding
+of other types of multi-byte locales.
+
+Use C<undef> as the first parameter to this function to get the effect
+of passing NULL as the first parameter to C<wctomb>. This resets any
+shift state to its initial value. The return value is undefined if
+C<wcrtomb> was substituted, so you should never rely on it.
+
+When the first parameter is a scalar, the code point contained in the
+scalar second parameter is converted into a multi-byte string and stored
+into the first parameter scalar. This is based on the locale that
+currently underlies the program, regardless of whether or not the
+function is called from Perl code that is within the scope of S<C<use
+locale>>. The return value is the number of bytes stored; or negative
+if the code point isn't representable in the current locale. Perl makes
+no attempt at hiding from your code any differences in the C<errno>
+setting between C<wctomb> and C<wcrtomb>. It does set C<errno> to 0
+before calling them.
=item C<write>
$sigset = POSIX::SigSet->new( &POSIX::SIGUSR1 );
+Throws an error if any of the signals supplied cannot be added to the
+set.
+
=item C<addset>
Add a signal to a SigSet object.
=back
+=head1 RESOURCE CONSTANTS
+
+Imported with the C<:sys_resource_h> tag.
+
+=over 8
+
+=item Constants
+
+Added in Perl v5.28:
+
+C<PRIO_PROCESS> C<PRIO_PGRP> C<PRIO_USER>
+
+=back
+
=head1 SYSTEM CONFIGURATION
=over 8
C<HUGE_VAL>
+Added in Perl v5.22:
+
C<FP_ILOGB0> C<FP_ILOGBNAN> C<FP_INFINITE> C<FP_NAN> C<FP_NORMAL> C<FP_SUBNORMAL> C<FP_ZERO>
C<INFINITY> C<NAN> C<Inf> C<NaN>
C<M_1_PI> C<M_2_PI> C<M_2_SQRTPI> C<M_E> C<M_LN10> C<M_LN2> C<M_LOG10E> C<M_LOG2E> C<M_PI>
C<SIGKILL> C<SIGPIPE> C<SIGQUIT> C<SIGSEGV> C<SIGSTOP> C<SIGTERM> C<SIGTSTP> C<SIGTTIN> C<SIGTTOU>
C<SIGUSR1> C<SIGUSR2> C<SIG_BLOCK> C<SIG_DFL> C<SIG_ERR> C<SIG_IGN> C<SIG_SETMASK>
C<SIG_UNBLOCK>
+
+Added in Perl v5.24:
+
C<ILL_ILLOPC> C<ILL_ILLOPN> C<ILL_ILLADR> C<ILL_ILLTRP> C<ILL_PRVOPC> C<ILL_PRVREG> C<ILL_COPROC>
C<ILL_BADSTK> C<FPE_INTDIV> C<FPE_INTOVF> C<FPE_FLTDIV> C<FPE_FLTOVF> C<FPE_FLTUND> C<FPE_FLTRES>
C<FPE_FLTINV> C<FPE_FLTSUB> C<SEGV_MAPERR> C<SEGV_ACCERR> C<BUS_ADRALN> C<BUS_ADRERR>
=item Constants
+Added in Perl v5.24:
+
C<WSAEINTR> C<WSAEBADF> C<WSAEACCES> C<WSAEFAULT> C<WSAEINVAL> C<WSAEMFILE> C<WSAEWOULDBLOCK>
C<WSAEINPROGRESS> C<WSAEALREADY> C<WSAENOTSOCK> C<WSAEDESTADDRREQ> C<WSAEMSGSIZE>
C<WSAEPROTOTYPE> C<WSAENOPROTOOPT> C<WSAEPROTONOSUPPORT> C<WSAESOCKTNOSUPPORT>
https://perl5.git.perl.org / perl5.git / blobdiff