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,
       processor 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 porta‐
       ble.

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 depend‐
       ing on the architecture.

SEE ALSO
       kill(2), restart_syscall(2), sigaltstack(2), signal(2), signal(7)

COLOPHON
       This page is part of release 3.74 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 http://www.kernel.org/doc/man-pages/.



Linux                                       2013-07-30                               SIGRETURN(2)