sigreturn(2)
return from signal
LIBRARY
Lb libc
SYNOPSIS
In signal.h
Ft int
Fn sigreturn const ucontext_t *scp
DESCRIPTION
The
Fn 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
Fa 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
Fn sigreturn
system call
will fail and the thread context will remain unchanged
if one of the following occurs.
- Bq Er EFAULT
-
The
Fa scp
argument
points to memory that is not a valid part of the process
address space.
- Bq Er EINVAL
-
The process status longword is invalid or would improperly
raise the privilege level of the process.
HISTORY
The
Fn sigreturn
system call appeared in
BSD 4.3
