set and/or get signal stack context
cc . . . -lc
int sigstack(struct sigstack *ss, struct sigstack *oss);
sigstack 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
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:
void *ss_sp; /* signal stack pointer */
int ss_onstack; /* current status */
ss_sp is the initial value to be assigned to the stack
pointer when the system switches the process to the signal
stack. Note that this is not the address of the beginning
of the signal stack area. The
ss_onstack field of
oss is non-zero or zero depending on whether the process
is currently executing on the alternate signal stack or not.
If ss is not a NULL pointer, sigstack
sets the signal stack state to the value in the sigstack
structure pointed to by ss.
If ss 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.
Upon successful completion, a value of 0 is returned. Otherwise, a
value of -1 is returned and errno is set to indicate the
sigstack will fail and the signal stack context will
remain unchanged if the following occurs:
Either ss or oss points to memory that is not a
valid part of the process address space.
Signal stacks are not ``grown'' automatically, as is done for the
normal stack. If the stack overflows unpredictable results may
sigstack is conformant with:
X/Open Portability Guide Issue 4, Version 2 (Spec-1170).
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003