1SETJMP(3) Library functions SETJMP(3)
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6 setjmp, sigsetjmp - save stack context for non-local goto
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9 #include <setjmp.h>
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11 int setjmp(jmp_buf env);
12 int sigsetjmp(sigjmp_buf env, int savesigs);
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15 setjmp() and longjmp() are useful for dealing with errors and inter‐
16 rupts encountered in a low-level subroutine of a program. setjmp()
17 saves the stack context/environment in env for later use by longjmp().
18 The stack context will be invalidated if the function which called
19 setjmp() returns.
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21 sigsetjmp() is similar to setjmp(). If savesigs is non-zero, the set
22 of blocked signals is saved in env and will be restored if a sig‐
23 longjmp() is later performed with this env.
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26 setjmp() and sigsetjmp() return 0 if returning directly, and non-zero
27 when returning from longjmp() using the saved context.
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30 C89, C99, and POSIX.1-2001 specify setjmp(). POSIX.1-2001 specifies
31 sigsetjmp().
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34 POSIX does not specify whether setjmp() will save the signal context.
35 (In System V it will not. In 4.3BSD it will, and there is a function
36 _setjmp that will not.) If you want to save signal masks, use
37 sigsetjmp().
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39 setjmp() and sigsetjmp() make programs hard to understand and maintain.
40 If possible an alternative should be used.
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43 longjmp(3), siglongjmp(3)
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47 1997-03-02 SETJMP(3)