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SIGALTSTACK(2) Linux Programmer's Manual SIGALTSTACK(2)
sigaltstack - get or set alternate signal stack content
int sigaltstack(const stack_t *ss, stack_t *oss);
ss points to a signalstack structure defined in <signal.h> containing stack content
after the call.
oss if not NULL, points to a signalstack structure containing stack content before the
sigaction(2) may indicate that a signal should execute on an alternate stack. Where this
is the case, sigaltstack(2) stores the signal in an alternate stack structure ss where its
execution status may be examined prior to processing.
The sigaltstack struct is defined in <signal.h> as follows:
void *ss_sp /* SVID3 uses caddr_t ss_sp
ss_sp points to the stack structure.
specifies the stack state to SS_DISABLE or SS_ONSTACK as follows:
If ss is not NULL,the new state may be set to SS_DISABLE, which specifies that the
stack is to be disabled and ss_sp and ss_size are ignored. If SS_DISABLE is not
set, the stack will be enabled.
If oss is not NULL, the stack state may be either SS_ONSTACK or SS_DISABLE. The
value SS_ONSTACK indicates that the process is currently executing on the alternate
stack and that any attempt to modify it during execution will fail. The value
SS_DISABLE indicates that the current signal stack is disabled.
specifies the size of the stack.
The value SIGSTKSZ defines the average number of bytes used when allocating an alternate
stack area. The value MINSIGSTKSZ defines the minimum stack size for a signal handler.
When processing an alternate stack size, your program should include these values in the
stack requirement to plan for the overhead of the operating system.
sigaltstack(2) returns 0 on success and -1 on failure.
sigaltstack(2) sets errno for the following conditions:
EINVAL ss is not a null pointer the ss_flags member pointed to by ss contains flags other
ENOMEM The size of the alternate stack area is less than MINSIGSTKSZ.
EPERM An attempt was made to modify an active stack.
This function comforms to: XPG4-UNIX.
getcontext(2), sigaction(2), sigsetjmp(3).
Red Hat Linux 6.1 20 September 1999 SIGALTSTACK(2)
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