longjmp
Synopsis
#include <setjmp.h>
void longjmp(jmp_buf env, int val);
Status
Partially implemented
Conformance
IEEE Std 1003.1-2017
Description
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 andlongjmp()call.
Although longjmp() is an async-signal-safe function, if it is invoked from a signal handler which interrupted a
non-async-signal-safe function or equivalent (such as the processing equivalent to exit() performed after a return
from the initial call to main()), the behavior of any subsequent call to a non-async-signal-safe function or
equivalent 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
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
No errors are defined.
Tests
Untested
Known bugs
None