1LONGJMP(P) POSIX Programmer's Manual LONGJMP(P)
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6 longjmp - non-local goto
7
9 #include <setjmp.h>
10 void longjmp(jmp_buf env, int val);
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15 The longjmp() function shall restore the environment saved by the most
16 recent invocation of setjmp() in the same thread, with the correspond‐
17 ing jmp_buf argument. If there is no such invocation, or if the func‐
18 tion containing the invocation of setjmp() has terminated execution in
19 the interim, or if the invocation of setjmp() was within the scope of
20 an identifier with variably modified type and execution has left that
21 scope in the interim, the behavior is undefined. It is unspecified
22 whether longjmp() restores the signal mask, leaves the signal mask
23 unchanged, or restores it to its value at the time setjmp() was called.
24 All accessible objects have values, and all other components of the
26 abstract machine have state (for example, floating-point status flags
27 and open files), as of the time longjmp() was called, except that the
28 values of objects of automatic storage duration are unspecified if they
29 meet all the following conditions:
30 * They are local to the function containing the corresponding setjmp()
32 invocation.
33 * They do not have volatile-qualified type.
35 * They are changed between the setjmp() invocation and longjmp() call.
37 As it bypasses the usual function call and return mechanisms, longjmp()
39 shall execute correctly in contexts of interrupts, signals, and any of
40 their associated functions. However, if longjmp() is invoked from a
41 nested signal handler (that is, from a function invoked as a result of
42 a signal raised during the handling of another signal), the behavior is
43 undefined.
44 The effect of a call to longjmp() where initialization of the jmp_buf
46 structure was not performed in the calling thread is undefined.
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49 After longjmp() is completed, program execution continues as if the
50 corresponding invocation of setjmp() had just returned the value speci‐
51 fied by val. The longjmp() function shall not cause setjmp() to return
52 0; if val is 0, setjmp() shall return 1.
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55 No errors are defined.
56 The following sections are informative.
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60 None.
61
63 Applications whose behavior depends on the value of the signal mask
64 should not use longjmp() and setjmp(), since their effect on the signal
65 mask is unspecified, but should instead use the siglongjmp() and
66 sigsetjmp() functions (which can save and restore the signal mask under
67 application control).
68
70 None.
71
73 None.
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76 setjmp() , sigaction() , siglongjmp() , sigsetjmp() , the Base Defini‐
77 tions volume of IEEE Std 1003.1-2001, <setjmp.h>
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80 Portions of this text are reprinted and reproduced in electronic form
81 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
82 -- Portable Operating System Interface (POSIX), The Open Group Base
83 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
84 Electrical and Electronics Engineers, Inc and The Open Group. In the
85 event of any discrepancy between this version and the original IEEE and
86 The Open Group Standard, the original IEEE and The Open Group Standard
87 is the referee document. The original Standard can be obtained online
88 at http://www.opengroup.org/unix/online.html .
89IEEE/The Open Group 2003 LONGJMP(P)