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
13 longjmp — non-local goto
14
16 #include <setjmp.h>
17 void longjmp(jmp_buf env, int val);
19
21 The functionality described on this reference page is aligned with the
22 ISO C standard. Any conflict between the requirements described here
23 and the ISO C standard is unintentional. This volume of POSIX.1‐2008
24 defers to the ISO C standard.
25 The longjmp() function shall restore the environment saved by the most
27 recent invocation of setjmp() in the same process, with the correspond‐
28 ing jmp_buf argument. If the most recent invocation of setjmp() with
29 the corresponding jmp_buf occurred in another thread, or if there is no
30 such invocation, or if the function containing the invocation of
31 setjmp() has terminated execution in the interim, or if the invocation
32 of setjmp() was within the scope of an identifier with variably modi‐
33 fied type and execution has left that scope in the interim, the behav‐
34 ior is undefined. It is unspecified whether longjmp() restores the
35 signal mask, leaves the signal mask unchanged, or restores it to its
36 value at the time setjmp() was called.
37 All accessible objects have values, and all other components of the
39 abstract machine have state (for example, floating-point status flags
40 and open files), as of the time longjmp() was called, except that the
41 values of objects of automatic storage duration are unspecified if they
42 meet all the following conditions:
43 * They are local to the function containing the corresponding
45 setjmp() invocation.
46 * They do not have volatile-qualified type.
48 * They are changed between the setjmp() invocation and longjmp()
50 call.
51 As it bypasses the usual function call and return mechanisms, longjmp()
53 shall execute correctly in contexts of interrupts, signals, and any of
54 their associated functions. However, if longjmp() is invoked from a
55 nested signal handler (that is, from a function invoked as a result of
56 a signal raised during the handling of another signal), the behavior is
57 undefined.
58 The effect of a call to longjmp() where initialization of the jmp_buf
60 structure was not performed in the calling thread is undefined.
61
63 After longjmp() is completed, program execution continues as if the
64 corresponding invocation of setjmp() had just returned the value speci‐
65 fied by val. The longjmp() function shall not cause setjmp() to return
66 0; if val is 0, setjmp() shall return 1.
67
69 No errors are defined.
70 The following sections are informative.
72
74 None.
75
77 Applications whose behavior depends on the value of the signal mask
78 should not use longjmp() and setjmp(), since their effect on the signal
79 mask is unspecified, but should instead use the siglongjmp() and
80 sigsetjmp() functions (which can save and restore the signal mask under
81 application control).
82
84 None.
85
87 None.
88
90 setjmp(), sigaction(), siglongjmp(), sigsetjmp()
91 The Base Definitions volume of POSIX.1‐2008, <setjmp.h>
93
95 Portions of this text are reprinted and reproduced in electronic form
96 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
97 -- Portable Operating System Interface (POSIX), The Open Group Base
98 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
99 cal and Electronics Engineers, Inc and The Open Group. (This is
100 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
101 event of any discrepancy between this version and the original IEEE and
102 The Open Group Standard, the original IEEE and The Open Group Standard
103 is the referee document. The original Standard can be obtained online
104 at http://www.unix.org/online.html .
105 Any typographical or formatting errors that appear in this page are
107 most likely to have been introduced during the conversion of the source
108 files to man page format. To report such errors, see https://www.ker‐
109 nel.org/doc/man-pages/reporting_bugs.html .
110IEEE/The Open Group 2013 LONGJMP(3P)