NAME

       sigreturn — return from signal

LIBRARY

       Standard C Library (libc, -lc)

SYNOPSIS

       #include <signal.h>

       int
       sigreturn(const ucontext_t *scp);

DESCRIPTION

       The  sigreturn()  system  call allows users to atomically unmask, switch stacks, and return from a signal
       context.  The processes signal mask and stack status are restored from the context structure  pointed  to
       by  scp.   The system call does not return; the users stack pointer, frame pointer, argument pointer, and
       processor status longword are restored from the context.  Execution resumes at the  specified  pc.   This
       system  call is used by the trampoline code and longjmp(3) when returning from a signal to the previously
       executing program.

RETURN VALUES

       If successful, the system call does not return.  Otherwise, a value of -1 is returned and errno is set to
       indicate the error.

ERRORS

       The sigreturn() system call will fail and the process  context  will  remain  unchanged  if  one  of  the
       following occurs.

       [EFAULT]           The  scp  argument  points  to  memory that is not a valid part of the process address
                          space.

       [EINVAL]           The process status longword is invalid or would improperly raise the  privilege  level
                          of the process.

SEE ALSO

       sigaction(2), setjmp(3), ucontext(3)

HISTORY

       The sigreturn() system call appeared in 4.3BSD.

Debian                                            June 4, 1993                                      SIGRETURN(2)