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sigstack - Set and get the signal stack context
struct sigstack *instack,
struct sigstack *outstack );
Interfaces documented on this reference page conform to industry standards
sigstack(): XSH4.0, XSH4.2, XSH5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
instack Points to the structure describing the new signal stack.
Points to the structure where the current signal stack state is
The sigstack() function defines an alternate stack on which signals are to
If the value of the instack parameter is nonzero, it points to a sigstack
structure, which has the following members:
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 portable applications.
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
[Tru64 UNIX] The instack or outstack parameter points outside of
the address space of the process.
[EPERM] An attempt was made to modify an active stack.
Functions: sigaction(2), sigvec(2), setjmp(3)
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