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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.

SEE ALSO

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

HISTORY

     The sigreturn() system call appeared in 4.3BSD.