siglongjmp(3)                                             siglongjmp(3)

  setjmp()

  NAME

    setjmp(), longjmp(), sigsetjmp(), siglongjmp() - non-local jumps

  SYNOPSIS

    #include 

    int setjmp (jmp_buf env)
    void longjmp (jmp_buf env, int val)
    int sigsetjmp (sigjmp_buf env, int savemask)
    void siglongjmp (sigjmp_buf env, int val)

  DESCRIPTION

    The setjmp(3) and sigsetjmp(3) functions save their calling environment in
    env. Each of these functions returns 0.

    The corresponding longjmp(3) functions restore the environment saved by
    their most recent respective invocations of the setjmp(3) function. They
    then return so that program execution continues as if the corresponding
    invocation of the setjmp(3) call had just returned the value specified by
    val, instead of 0.

    Sigsetjmp(3) and siglongjmp(3) save and restore the signal mask if the
    argument savemask is non-zero; otherwise they behave identically with
    setjmp(3) and longjmp(3).

    The longjmp(3) routines may not be called after the routine which called
    the setjmp(3) routines returns.

    All accessible objects have values as of the time longjmp(3) routine was
    called, except that the values of objects of automatic storage invocation
    duration that do not have the volatile type and have been changed between
    the setjmp(3) invocation and longjmp(3) call are indeterminate.

    Pairs of calls may be intermixed, i.e. both sigsetjmp(3) and siglongjmp(3)
    and setjmp(3) and longjmp(3) combinations may be used in the same program,
    however, individual calls may not, e.g. the env argument to setjmp(3) may
    not be passed to siglongjmp(3).

  RETURN VALUES

    When invoked directly, setjmp(3) returns zero; when invoked as part of
    longjmp(3), setjmp(3) returns non-zero.

    When invoked directly, sigsetjmp(3) returns zero; when invoked as part of
    siglongjmp(3), sigsetjmp(3) returns non-zero.

  SEE ALSO

    sigaction(2)

    signal(2)

  USAGE NOTES

    All of these functions are thread safe.

    None of these functions are async-signal safe.