rt_sigsuspend(2) [plan9 man page]

SIGSUSPEND(2)						     Linux Programmer's Manual						     SIGSUSPEND(2)

NAME

       sigsuspend, rt_sigsuspend - wait for a signal

SYNOPSIS

       #include <signal.h>

       int sigsuspend(const sigset_t *mask);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       sigsuspend(): _POSIX_C_SOURCE

DESCRIPTION

       sigsuspend()  temporarily  replaces  the signal mask of the calling process with the mask given by mask and then suspends the process until
       delivery of a signal whose action is to invoke a signal handler or to terminate a process.

       If the signal terminates the process, then sigsuspend() does not return.  If the signal is caught, then sigsuspend() returns after the sig-
       nal handler returns, and the signal mask is restored to the state before the call to sigsuspend().

       It is not possible to block SIGKILL or SIGSTOP; specifying these signals in mask, has no effect on the process's signal mask.

RETURN VALUE

       sigsuspend() always returns -1, with errno set to indicate the error (normally, EINTR).

ERRORS

       EFAULT mask points to memory which is not a valid part of the process address space.

       EINTR  The call was interrupted by a signal; signal(7).

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008.

NOTES

       Normally, sigsuspend() is used in conjunction with sigprocmask(2) in order to prevent delivery of a signal during the execution of a criti-
       cal code section.  The caller first blocks the signals with sigprocmask(2).  When the critical code has completed, the  caller  then  waits
       for the signals by calling sigsuspend() with the signal mask that was returned by sigprocmask(2) (in the oldset argument).

       See sigsetops(3) for details on manipulating signal sets.

   C library/kernel differences
       The  original  Linux  system  call  was	named sigsuspend().  However, with the addition of real-time signals in Linux 2.2, the fixed-size,
       32-bit sigset_t type supported by that system call was no longer fit for purpose.  Consequently, a new system  call,  rt_sigsuspend(),  was
       added  to  support  an enlarged sigset_t type.  The new system call takes a second argument, size_t sigsetsize, which specifies the size in
       bytes of the signal set in mask.  This argument is currently required to have the value sizeof(sigset_t) (or  the  error  EINVAL  results).
       The glibc sigsuspend() wrapper function hides these details from us, transparently calling rt_sigsuspend() when the kernel provides it.

SEE ALSO

       kill(2), pause(2), sigaction(2), signal(2), sigprocmask(2), sigwaitinfo(2), sigsetops(3), sigwait(3), signal(7)

COLOPHON

       This  page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15							     SIGSUSPEND(2)

SIGSUSPEND(2)						     Linux Programmer's Manual						     SIGSUSPEND(2)

NAME

       sigsuspend, rt_sigsuspend - wait for a signal

SYNOPSIS

       #include <signal.h>

       int sigsuspend(const sigset_t *mask);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       sigsuspend(): _POSIX_C_SOURCE

DESCRIPTION

       sigsuspend()  temporarily  replaces  the signal mask of the calling process with the mask given by mask and then suspends the process until
       delivery of a signal whose action is to invoke a signal handler or to terminate a process.

       If the signal terminates the process, then sigsuspend() does not return.  If the signal is caught, then sigsuspend() returns after the sig-
       nal handler returns, and the signal mask is restored to the state before the call to sigsuspend().

       It is not possible to block SIGKILL or SIGSTOP; specifying these signals in mask, has no effect on the process's signal mask.

RETURN VALUE

       sigsuspend() always returns -1, with errno set to indicate the error (normally, EINTR).

ERRORS

       EFAULT mask points to memory which is not a valid part of the process address space.

       EINTR  The call was interrupted by a signal; signal(7).

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008.

NOTES

       Normally, sigsuspend() is used in conjunction with sigprocmask(2) in order to prevent delivery of a signal during the execution of a criti-
       cal code section.  The caller first blocks the signals with sigprocmask(2).  When the critical code has completed, the  caller  then  waits
       for the signals by calling sigsuspend() with the signal mask that was returned by sigprocmask(2) (in the oldset argument).

       See sigsetops(3) for details on manipulating signal sets.

   C library/kernel differences
       The  original  Linux  system  call  was	named sigsuspend().  However, with the addition of real-time signals in Linux 2.2, the fixed-size,
       32-bit sigset_t type supported by that system call was no longer fit for purpose.  Consequently, a new system  call,  rt_sigsuspend(),  was
       added  to  support  an enlarged sigset_t type.  The new system call takes a second argument, size_t sigsetsize, which specifies the size in
       bytes of the signal set in mask.  This argument is currently required to have the value sizeof(sigset_t) (or  the  error  EINVAL  results).
       The glibc sigsuspend() wrapper function hides these details from us, transparently calling rt_sigsuspend() when the kernel provides it.

SEE ALSO

       kill(2), pause(2), sigaction(2), signal(2), sigprocmask(2), sigwaitinfo(2), sigsetops(3), sigwait(3), signal(7)

COLOPHON

       This  page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15							     SIGSUSPEND(2)