SIGRETURN(2) |
FreeBSD System Calls Manual |
SIGRETURN(2) |
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 thread's 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 thread 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.
HISTORY
The
sigreturn() system call appeared in
4.3BSD.