LONGJMP(3P)               POSIX Programmer's Manual              LONGJMP(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       longjmp — non-local goto

SYNOPSIS         top

       #include <setjmp.h>

       void longjmp(jmp_buf env, int val);

DESCRIPTION         top

       The functionality described on this reference page is aligned with
       the ISO C standard. Any conflict between the requirements described
       here and the ISO C standard is unintentional. This volume of
       POSIX.1‐2008 defers to the ISO C standard.

       The longjmp() function shall restore the environment saved by the
       most recent invocation of setjmp() in the same process, with the
       corresponding jmp_buf argument. If the most recent invocation of
       setjmp() with the corresponding jmp_buf occurred in another thread,
       or if there is no such invocation, or if the function containing the
       invocation of setjmp() has terminated execution in the interim, or if
       the invocation of setjmp() was within the scope of an identifier with
       variably modified type and execution has left that scope in the
       interim, the behavior is undefined.  It is unspecified whether
       longjmp() restores the signal mask, leaves the signal mask unchanged,
       or restores it to its value at the time setjmp() was called.

       All accessible objects have values, and all other components of the
       abstract machine have state (for example, floating-point status flags
       and open files), as of the time longjmp() was called, except that the
       values of objects of automatic storage duration are unspecified if
       they meet all the following conditions:

        *  They are local to the function containing the corresponding
           setjmp() invocation.

        *  They do not have volatile-qualified type.

        *  They are changed between the setjmp() invocation and longjmp()

       As it bypasses the usual function call and return mechanisms,
       longjmp() shall execute correctly in contexts of interrupts, signals,
       and any of their associated functions. However, if longjmp() is
       invoked from a nested signal handler (that is, from a function
       invoked as a result of a signal raised during the handling of another
       signal), the behavior is undefined.

       The effect of a call to longjmp() where initialization of the jmp_buf
       structure was not performed in the calling thread is undefined.

RETURN VALUE         top

       After longjmp() is completed, program execution continues as if the
       corresponding invocation of setjmp() had just returned the value
       specified by val.  The longjmp() function shall not cause setjmp() to
       return 0; if val is 0, setjmp() shall return 1.

ERRORS         top

       No errors are defined.

       The following sections are informative.

EXAMPLES         top



       Applications whose behavior depends on the value of the signal mask
       should not use longjmp() and setjmp(), since their effect on the
       signal mask is unspecified, but should instead use the siglongjmp()
       and sigsetjmp() functions (which can save and restore the signal mask
       under application control).

RATIONALE         top




SEE ALSO         top

       setjmp(3p), sigaction(3p), siglongjmp(3p), sigsetjmp(3p)

       The Base Definitions volume of POSIX.1‐2008, setjmp.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) In the event of any discrepancy between this version and
       the original IEEE and The Open Group Standard, the original IEEE and
       The Open Group Standard is the referee document. The original
       Standard can be obtained online at .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see .

IEEE/The Open Group                 2013                         LONGJMP(3P)

Pages that refer to this page: setjmp.h(0p)exit(3p)ftw(3p)_longjmp(3p)setjmp(3p)sigaction(3p)siglongjmp(3p)