1SIGSETJMP(P)               POSIX Programmer's Manual              SIGSETJMP(P)
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NAME

6       sigsetjmp - set jump point for a non-local goto
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SYNOPSIS

9       #include <setjmp.h>
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11       int sigsetjmp(sigjmp_buf env, int savemask);
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DESCRIPTION

15       The  sigsetjmp() function shall be equivalent to the setjmp() function,
16       except as follows:
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18        * References to setjmp() are equivalent to sigsetjmp().
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20        * References to longjmp() are equivalent to siglongjmp().
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22        * If the value of the savemask argument is not  0,  sigsetjmp()  shall
23          also  save  the current signal mask of the calling thread as part of
24          the calling environment.
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RETURN VALUE

27       If the return is from a successful direct invocation, sigsetjmp() shall
28       return  0.  If  the  return is from a call to siglongjmp(), sigsetjmp()
29       shall return a non-zero value.
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ERRORS

32       No errors are defined.
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34       The following sections are informative.
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EXAMPLES

37       None.
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APPLICATION USAGE

40       The distinction  between  setjmp()/  longjmp()  and  sigsetjmp()/  sig‐
41       longjmp()  is only significant for programs which use sigaction(), sig‐
42       procmask(), or sigsuspend().
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44       Note that since this function is defined in terms of setjmp(), if save‐
45       mask is zero, it is unspecified whether the signal mask is saved.
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RATIONALE

48       The  ISO C  standard specifies various restrictions on the usage of the
49       setjmp() macro in order to permit implementors to recognize the name in
50       the  compiler and not implement an actual function. These same restric‐
51       tions apply to the sigsetjmp() macro.
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53       There are processors that cannot easily support these calls,  but  this
54       was not considered a sufficient reason to exclude them.
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56       4.2  BSD,  4.3  BSD, and XSI-conformant systems provide functions named
57       _setjmp() and _longjmp() that, together with  setjmp()  and  longjmp(),
58       provide  the  same  functionality  as  sigsetjmp() and siglongjmp(). On
59       those systems, setjmp() and longjmp() save and  restore  signal  masks,
60       while  _setjmp()  and  _longjmp()  do not. On System V Release 3 and in
61       corresponding issues of the SVID, setjmp() and longjmp() are explicitly
62       defined not to save and restore signal masks. In order to permit exist‐
63       ing practice in both cases, the relation of setjmp() and  longjmp()  to
64       signal  masks  is  not specified, and a new set of functions is defined
65       instead.
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67       The longjmp() and siglongjmp() functions operate  as  in  the  previous
68       issue  provided the matching setjmp() or sigsetjmp() has been performed
69       in the same thread.  Non-local  jumps  into  contexts  saved  by  other
70       threads  would  be at best a questionable practice and were not consid‐
71       ered worthy of standardization.
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FUTURE DIRECTIONS

74       None.
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SEE ALSO

77       siglongjmp() , signal() , sigprocmask() , sigsuspend() , the Base Defi‐
78       nitions volume of IEEE Std 1003.1-2001, <setjmp.h>
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81       Portions  of  this text are reprinted and reproduced in electronic form
82       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
83       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
84       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
85       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
86       event of any discrepancy between this version and the original IEEE and
87       The  Open Group Standard, the original IEEE and The Open Group Standard
88       is the referee document. The original Standard can be  obtained  online
89       at http://www.opengroup.org/unix/online.html .
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93IEEE/The Open Group                  2003                         SIGSETJMP(P)
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