NAME
sigreturn —
return from signal
LIBRARY
library “libc”
SYNOPSIS
#include
<signal.h>
int
sigreturn(const
ucontext_t *scp);
DESCRIPTION
Thesigreturn()
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.
SEE ALSO
HISTORY
The sigreturn() system call appeared in
4.3BSD.