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
       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), restart_syscall(2), sigaltstack(2), signal(2), signal(7)

COLOPHON

       This page is part of release 3.54 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/.