1LONGJMP(3P) POSIX Programmer's Manual LONGJMP(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 longjmp - non-local goto
13
15 #include <setjmp.h>
16 void longjmp(jmp_buf env, int val);
18
21 The longjmp() function shall restore the environment saved by the most
22 recent invocation of setjmp() in the same thread, with the correspond‐
23 ing jmp_buf argument. If there is no such invocation, or if the func‐
24 tion containing the invocation of setjmp() has terminated execution in
25 the interim, or if the invocation of setjmp() was within the scope of
26 an identifier with variably modified type and execution has left that
27 scope in the interim, the behavior is undefined. It is unspecified
28 whether longjmp() restores the signal mask, leaves the signal mask
29 unchanged, or restores it to its value at the time setjmp() was called.
30 All accessible objects have values, and all other components of the
32 abstract machine have state (for example, floating-point status flags
33 and open files), as of the time longjmp() was called, except that the
34 values of objects of automatic storage duration are unspecified if they
35 meet all the following conditions:
36 * They are local to the function containing the corresponding setjmp()
38 invocation.
39 * They do not have volatile-qualified type.
41 * They are changed between the setjmp() invocation and longjmp() call.
43 As it bypasses the usual function call and return mechanisms, longjmp()
45 shall execute correctly in contexts of interrupts, signals, and any of
46 their associated functions. However, if longjmp() is invoked from a
47 nested signal handler (that is, from a function invoked as a result of
48 a signal raised during the handling of another signal), the behavior is
49 undefined.
50 The effect of a call to longjmp() where initialization of the jmp_buf
52 structure was not performed in the calling thread is undefined.
53
55 After longjmp() is completed, program execution continues as if the
56 corresponding invocation of setjmp() had just returned the value speci‐
57 fied by val. The longjmp() function shall not cause setjmp() to return
58 0; if val is 0, setjmp() shall return 1.
59
61 No errors are defined.
62 The following sections are informative.
64
66 None.
67
69 Applications whose behavior depends on the value of the signal mask
70 should not use longjmp() and setjmp(), since their effect on the signal
71 mask is unspecified, but should instead use the siglongjmp() and
72 sigsetjmp() functions (which can save and restore the signal mask under
73 application control).
74
76 None.
77
79 None.
80
82 setjmp(), sigaction(), siglongjmp(), sigsetjmp(), the Base Definitions
83 volume of IEEE Std 1003.1-2001, <setjmp.h>
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86 Portions of this text are reprinted and reproduced in electronic form
87 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
88 -- Portable Operating System Interface (POSIX), The Open Group Base
89 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
90 Electrical and Electronics Engineers, Inc and The Open Group. In the
91 event of any discrepancy between this version and the original IEEE and
92 The Open Group Standard, the original IEEE and The Open Group Standard
93 is the referee document. The original Standard can be obtained online
94 at http://www.opengroup.org/unix/online.html .
95IEEE/The Open Group 2003 LONGJMP(3P)