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

NAME

       sigreturn - return from signal handler and cleanup stack frame

SYNOPSIS

       int sigreturn(unsigned long __unused);

DESCRIPTION

       When  the  Linux  kernel  creates the stack frame for a signal handler, a call to sigreturn() is inserted into the stack frame so that upon
       return from the signal handler, sigreturn() will be called.

       This sigreturn() call undoes everything that was done--changing the process's signal mask, switching stacks (see sigaltstack(2))--in  order
       to  invoke  the signal handler: it restores the process's signal mask, switches stacks, and restores the process's context (registers, pro-
       cessor flags), so that the process directly resumes execution at the point where it was interrupted by the signal.

RETURN VALUE

       sigreturn() never returns.

FILES

       /usr/src/linux/arch/i386/kernel/signal.c
       /usr/src/linux/arch/alpha/kernel/entry.S

CONFORMING TO

       sigreturn() is specific to Linux and should not be used in programs intended to be portable.

NOTES

       The sigreturn() call is used by the kernel to implement signal handlers.  It should never be called directly.  Better yet, the specific use
       of the __unused argument varies depending on the architecture.

SEE ALSO

       kill(2), sigaltstack(2), signal(2), signal(7)

COLOPHON

       This  page is part of release 3.25 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2008-06-26							      SIGRETURN(2)