NAME

sigstack − set and/or get signal stack context

SYNOPSIS

#include <signal.h>

struct sigstack {
caddr_tss_sp;
intss_onstack;
};

sigstack(ss, oss)
struct sigstack ∗ss, ∗oss;

DESCRIPTION

Sigstack allows users to define an alternate stack on which signals are to be processed.  If ss is non-zero, it specifies a signal stack on which to deliver signals and tells the system if the process is currently executing on that stack.  When a signal’s action indicates its handler should execute on the signal stack (specified with a sigvec(2) call), the system checks to see if the process is currently executing on that stack.  If the process is not currently executing on the signal stack, the system arranges a switch to the signal stack for the duration of the signal handler’s execution. If oss is non-zero, the current signal stack state is returned. 

NOTES

Signal stacks are not “grown” automatically, as is done for the normal stack.  If the stack overflows unpredictable results may occur. 

RETURN VALUE

Upon successful completion, a value of 0 is returned.  Otherwise, a value of −1 is returned and errno is set to indicate the error. 

ERRORS

Sigstack will fail and the signal stack context will remain unchanged if one of the following occurs. 

[EFAULT] Either ss or oss points to memory which is not a valid part of the process address space. 

SEE ALSO

sigvec(2), setjmp(3), signal(3)

Sun Release 2.0  —  Last change: 29 August 1983