sigstack(3UCB) SunOS/BSD Compatibility Library Functions sigstack(3UCB)NAMEsigstack - set and/or get signal stack context
SYNOPSIS
/usr/ucb/cc [ flag ... ] file ...
#include <signal.h>
int sigstack(nss, oss)
struct sigstack *nss, *oss;
DESCRIPTION
The sigstack() function allows users to define an alternate stack,
called the "signal stack", on which signals are to be processed. When
a signal's action indicates its handler should execute on the signal
stack (specified with a sigvec(3UCB) 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.
A signal stack is specified by a sigstack() structure, which includes
the following members:
char *ss_sp; /* signal stack pointer */
int ss_onstack; /* current status */
The ss_sp member is the initial value to be assigned to the stack
pointer when the system switches the process to the signal stack. Note
that, on machines where the stack grows downwards in memory, this is
not the address of the beginning of the signal stack area. The
ss_onstack member is zero or non-zero depending on whether the process
is currently executing on the signal stack or not.
If nss is not a null pointer, sigstack() sets the signal stack state to
the value in the sigstack() structure pointed to by nss. If nss is a
null pointer, the signal stack state will be unchanged. If oss is not
a null pointer, the current signal stack state is stored in the
sigstack() structure pointed to by oss.
RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, −1 is returned
and errno is set to indicate the error.
ERRORS
The sigstack() function will fail and the signal stack context will
remain unchanged if one of the following occurs.
EFAULT Either nss or oss points to memory that is not a valid part
of the process address space.
SEE ALSOcc(1B), sigaltstack(2), sigvec(3UCB), signal(3C)WARNINGS
Signal stacks are not "grown" automatically, as is done for the normal
stack. If the stack overflows unpredictable results may occur.
NOTES
Use of these interfaces should be restricted to only applications writ‐
ten on BSD platforms. Use of these interfaces with any of the system
libraries or in multi-threaded applications is unsupported.
SunOS 5.10 30 Oct 2007 sigstack(3UCB)
