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sigaction(2): Extend description of async-signal safe functions:
* Improve description when unsafe functions are unsafe. * Add various safe functions from POSIX.1-2008 and Austin Group issue #692.
This commit is contained in:
Jilles Tjoelker
parent
33eebb6a75
commit
f8732c7fc3
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=251196
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@ -28,7 +28,7 @@
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.\" From: @(#)sigaction.2 8.2 (Berkeley) 4/3/94
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.\" $FreeBSD$
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.\"
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.Dd September 27, 2012
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.Dd May 31, 2013
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.Dt SIGACTION 2
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.Os
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.Sh NAME
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@ -346,13 +346,19 @@ Any attempt to do so will be silently ignored.
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The following functions are either reentrant or not interruptible
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by signals and are async-signal safe.
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Therefore applications may
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invoke them, without restriction, from signal-catching functions:
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invoke them, without restriction, from signal-catching functions
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or from a child process after calling
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.Xr fork 2
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in a multi-threaded process:
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.Pp
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Base Interfaces:
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.Pp
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.Fn _Exit ,
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.Fn _exit ,
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.Fn accept ,
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.Fn access ,
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.Fn alarm ,
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.Fn bind ,
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.Fn cfgetispeed ,
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.Fn cfgetospeed ,
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.Fn cfsetispeed ,
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@ -361,41 +367,65 @@ Base Interfaces:
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.Fn chmod ,
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.Fn chown ,
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.Fn close ,
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.Fn connect ,
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.Fn creat ,
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.Fn dup ,
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.Fn dup2 ,
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.Fn execl ,
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.Fn execle ,
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.Fn execv ,
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.Fn execve ,
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.Fn fchdir ,
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.Fn fchmod ,
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.Fn fchown ,
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.Fn fcntl ,
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.Fn fork ,
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.Fn fpathconf ,
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.Fn fstat ,
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.Fn fsync ,
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.Fn ftruncate ,
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.Fn getegid ,
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.Fn geteuid ,
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.Fn getgid ,
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.Fn getgroups ,
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.Fn getpeername ,
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.Fn getpgrp ,
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.Fn getpid ,
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.Fn getppid ,
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.Fn getsockname ,
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.Fn getsockopt ,
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.Fn getuid ,
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.Fn kill ,
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.Fn link ,
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.Fn listen ,
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.Fn lseek ,
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.Fn lstat ,
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.Fn mkdir ,
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.Fn mkfifo ,
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.Fn mknod ,
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.Fn open ,
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.Fn pathconf ,
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.Fn pause ,
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.Fn pipe ,
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.Fn poll ,
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.Fn pselect ,
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.Fn pthread_sigmask ,
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.Fn raise ,
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.Fn read ,
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.Fn readlink ,
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.Fn recv ,
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.Fn recvfrom ,
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.Fn recvmsg ,
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.Fn rename ,
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.Fn rmdir ,
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.Fn select ,
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.Fn send ,
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.Fn sendmsg ,
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.Fn sendto ,
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.Fn setgid ,
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.Fn setpgid ,
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.Fn setsid ,
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.Fn setsockopt ,
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.Fn setuid ,
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.Fn shutdown ,
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.Fn sigaction ,
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.Fn sigaddset ,
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.Fn sigdelset ,
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@ -407,8 +437,11 @@ Base Interfaces:
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.Fn sigprocmask ,
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.Fn sigsuspend ,
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.Fn sleep ,
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.Fn sockatmark ,
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.Fn socket ,
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.Fn socketpair ,
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.Fn stat ,
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.Fn sysconf ,
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.Fn symlink ,
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.Fn tcdrain ,
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.Fn tcflow ,
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.Fn tcflush ,
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@ -427,11 +460,16 @@ Base Interfaces:
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.Fn waitpid ,
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.Fn write .
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.Pp
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X/Open Systems Interfaces:
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.Pp
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.Fn sigpause ,
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.Fn sigset ,
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.Fn utimes .
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.Pp
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Realtime Interfaces:
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.Pp
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.Fn aio_error ,
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.Fn clock_gettime ,
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.Fn sigpause ,
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.Fn timer_getoverrun ,
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.Fn aio_return ,
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.Fn fdatasync ,
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@ -439,27 +477,84 @@ Realtime Interfaces:
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.Fn timer_gettime ,
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.Fn aio_suspend ,
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.Fn sem_post ,
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.Fn sigset ,
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.Fn timer_settime .
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.Pp
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.Tn ANSI C
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Interfaces:
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Base Interfaces not specified as async-signal safe by
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.Tn POSIX :
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.Pp
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.Fn strcpy ,
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.Fn fpathconf ,
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.Fn pathconf ,
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.Fn sysconf .
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.Pp
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Base Interfaces not specified as async-signal safe by
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.Tn POSIX ,
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but planned to be:
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.Pp
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.Fn ffs ,
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.Fn htonl ,
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.Fn htons ,
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.Fn memccpy ,
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.Fn memchr ,
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.Fn memcmp ,
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.Fn memcpy ,
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.Fn memmove ,
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.Fn memset ,
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.Fn ntohl ,
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.Fn ntohs ,
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.Fn stpcpy ,
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.Fn stpncpy ,
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.Fn strcat ,
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.Fn strncpy ,
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.Fn strchr ,
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.Fn strcmp ,
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.Fn strcpy ,
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.Fn strcspn ,
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.Fn strlen ,
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.Fn strncat ,
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and perhaps some others.
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.Fn strncmp ,
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.Fn strncpy ,
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.Fn strnlen ,
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.Fn strpbrk ,
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.Fn strrchr ,
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.Fn strspn ,
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.Fn strstr ,
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.Fn strtok_r ,
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.Fn wcpcpy ,
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.Fn wcpncpy ,
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.Fn wcscat ,
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.Fn wcschr ,
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.Fn wcscmp ,
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.Fn wcscpy ,
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.Fn wcscspn ,
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.Fn wcslen ,
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.Fn wcsncat ,
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.Fn wcsncmp ,
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.Fn wcsncpy ,
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.Fn wcsnlen ,
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.Fn wcspbrk ,
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.Fn wcsrchr ,
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.Fn wcsspn ,
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.Fn wcsstr ,
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.Fn wcstok ,
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.Fn wmemchr ,
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.Fn wmemcmp ,
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.Fn wmemcpy ,
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.Fn wmemmove ,
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.Fn wmemset .
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.Pp
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Extension Interfaces:
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.Pp
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.Fn strlcpy ,
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.Fn strlcat .
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.Pp
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In addition, reading or writing
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.Va errno
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is async-signal safe.
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.Pp
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All functions not in the above lists are considered to be unsafe
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with respect to signals.
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That is to say, the behaviour of such
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functions when called from a signal handler is undefined.
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functions is undefined when they are called from a signal handler
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that interrupted an unsafe function.
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In general though, signal handlers should do little more than set a
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flag; most other actions are not safe.
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.Pp
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