sigstack(2)sigstack(2)Namesigstack - set or get signal stack context
Syntax
#include <signal.h>
struct sigstack {
caddr_t ss_sp;
int ss_onstack;
};
sigstack(ss, oss)
struct sigstack *ss, *oss;
Description
The system call allows users to define an alternate stack on which sig‐
nals are to be processed. If ss is nonzero, 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 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 nonzero, the current signal
stack state is returned.
Signal stacks are not grown'automatically, as is done for the normal
stack. If the stack overflows, unpredictable results may occur.
Return Values
Upon successful completion, a value of zero (0) is returned. Other‐
wise, a value of -1 is returned and errno is set to indicate the error.
Diagnostics
The system call fails and the signal stack context remains unchanged,
if one of the following occurs.
[EFAULT] Either ss or oss points to memory that is not a valid
part of the process address space.
See Alsosigvec(2), setjmp(3)sigstack(2)
