sigstack - Set and get the signal stack context
struct sigstack *instack,
struct sigstack *outstack );
Interfaces documented on this reference page conform to
industry standards as follows:
sigstack(): XSH4.0, XSH4.2, XSH5.0
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Points to the structure describing the new signal stack.
Points to the structure where the current signal stack
state is stored.
The sigstack() function defines an alternate stack on
which signals are to be processed.
If the value of the instack parameter is nonzero, it
points to a sigstack structure, which has the following
int ss_onstack; }
The value of instack->ss_sp specifies the stack pointer of
the new signal stack. The value of instack->ss_onstack
should be set to 1 if the process is currently running on
that stack; otherwise, it should be 0 (zero).
If the value of the instack parameter is 0 (that is, a
null pointer), the signal stack state is not set.
If the value of the outstack parameter is nonzero, it
points to a sigstack structure into which the sigstack()
function stores the current signal stack state. If the
value of the outstack parameter is 0 (zero), the previous
signal stack state is not reported.
When a signal occurs and its handler is to run on the signal
stack, the system checks to see if the process is
already running on that stack. If so, the process continues
to run on that stack even after the handler returns.
If not, the signal handler runs on the signal stack, and
the original stack is restored when the handler returns.
Use the sigaction() function to specify whether a given
signal handler routine is to run on the signal stack.
A signal stack does not automatically increase in size as
a normal stack does. If the stack overflows, unpredictable
results can occur.
The sigstack() function is defined as a LEGACY function by
the XSH specification. XSH recommends that sigaltstack()
rather than sigstack() be used when creating or rewriting
Upon successful completion, a value of 0 (zero) is
returned. Otherwise, a value of -1 is returned and errno
is set to indicate the error.
The sigstack() function sets errno to the specified value
for the following conditions: [Tru64 UNIX] The instack or
outstack parameter points outside of the address space of
the process. An attempt was made to modify an active
Functions: sigaction(2), sigvec(2), setjmp(3)
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