sigsetjmp(3C)                                       sigsetjmp(3C)



NAME
     sigsetjmp, siglongjmp - non-local goto

SYNOPSIS
     #include <setjmp.h>

     int sigsetjmp (env, savemask)
     sigjmpbuf env;
     int savemask;

     void siglongjmp (env, val)
     sigjmpbuf env;
     int val;

DESCRIPTION
     These POSIX functions are useful for dealing with errors and
     interrupts encountered in a low-level subroutine of a pro-
     gram.

     sigsetjmp saves the calling process's registers and stack
     environment in env (whose type, sigjmpbuf, is defined in
     the <setjmp.h> header file) for later use by siglongjmp.  If
     the value of the savemask argument is not zero, then sig-
     setjmp shall also save the process's current signal mask as
     part of the calling environment.  sigsetjmp then returns the
     value 0.

     siglongjmp restores the environment saved by the last call
     of sigsetjmp with the corresponding env argument.  If the
     env argument was initialized by a call to sigsetjmp with a
     non-zero savemask argument, then siglongjmp will also
     restore the process's saved signal mask.  After siglongjmp
     is completed, program execution continues as if the
     corresponding call of sigsetjmp (the caller of which must
     not itself have returned in the interim) had just returned
     the value val.  All accessible data had values as of the
     time siglongjmp was called.

     siglongjmp cannot cause sigsetjmp to return the value 0.  If
     siglongjmp is invoked with a second argument of 0, sigsetjmp
     will return 1.

SEE ALSO
     setjmp(3C), sigaction(2), sigaltstack(2), signal(2), sig-
     stack(2), sigvec(2).

WARNING
     If siglongjmp is called even though env was never primed by
     a call to sigsetjmp, or when the last such call was in a
     function which has since returned, absolute chaos is
     guaranteed.




Page 1                        CX/UX Programmer's Reference Manual

sigsetjmp(3C)                                       sigsetjmp(3C)



     sigsetjmp does not save the current notion of whether the
     process is executing on the signal stack.  The result is
     that a siglongjmp to some place on the signal stack leaves
     the signal stack state incorrect.



















































Page 2                        CX/UX Programmer's Reference Manual