SETJMP(3)                  POSIX Programmer's Manual                 SETJMP(3)



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

NNAAMMEE
       setjmp -- set jump point for a non-local goto

SSYYNNOOPPSSIISS
       #include <setjmp.h>

       int setjmp(jmp_buf _e_n_v);

DDEESSCCRRIIPPTTIIOONN
       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.1-2017
       defers to the ISO C standard.

       A call to _s_e_t_j_m_p() shall save the calling environment in its _e_n_v
       argument for later use by _l_o_n_g_j_m_p().

       It is unspecified whether _s_e_t_j_m_p() is a macro or a function. If a macro
       definition is suppressed in order to access an actual function, or a
       program defines an external identifier with the name _s_e_t_j_m_p, the
       behavior is undefined.

       An application shall ensure that an invocation of _s_e_t_j_m_p() appears in
       one of the following contexts only:

        *  The entire controlling expression of a selection or iteration
           statement

        *  One operand of a relational or equality operator with the other
           operand an integral constant expression, with the resulting
           expression being the entire controlling expression of a selection
           or iteration statement

        *  The operand of a unary ''!!''  operator with the resulting expression
           being the entire controlling expression of a selection or iteration

        *  The entire expression of an expression statement (possibly cast to
           vvooiidd)

       If the invocation appears in any other context, the behavior is
       undefined.

RREETTUURRNN VVAALLUUEE
       If the return is from a direct invocation, _s_e_t_j_m_p() shall return 0. If
       the return is from a call to _l_o_n_g_j_m_p(), _s_e_t_j_m_p() shall return a non-
       zero value.

EERRRROORRSS
       No errors are defined.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       In general, _s_i_g_s_e_t_j_m_p() is more useful in dealing with errors and
       interrupts encountered in a low-level subroutine of a program.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _l_o_n_g_j_m_p(), _s_i_g_s_e_t_j_m_p()

       The Base Definitions volume of POSIX.1-2017, <<sseettjjmmpp..hh>>

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  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 http://www.opengroup.org/unix/online.html .

       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
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                            SETJMP(3)
