WIFEXITEDstatus

WIFEXITEDstatus is a term referring to the use of the WIFEXITED macro in the POSIX wait/status mechanism. In POSIX systems, a process can wait for child processes and obtain a status value that encodes how the child terminated. WIFEXITED(status) is a macro defined in sys/wait.h that tests whether the child terminated normally by calling exit or _Exit. If WIFEXITED(status) is true, the exit status is obtained with WEXITSTATUS(status), which yields the value passed to exit or _Exit, typically in the range 0 to 255.

The WIFEXITED macro is part of a family of status macros used with wait, waitpid, or similar interfaces. Other macros include WIFSIGNALED, WIFSTOPPED, WTERMSIG, and WEXITSTATUS. Together, they allow a program to distinguish between normal termination, termination due to a signal, or being stopped for tracing or debugging. For normal termination, WEXITSTATUS gives the actual exit code; for signal-based termination, WTERMSIG reveals the signal number.

Usage pattern commonly involves calling waitpid (or wait) to obtain a status value, then testing with WIFEXITED(status). If true, a programmer can retrieve the exit code via WEXITSTATUS(status). If not, other macros can be used to determine whether the process was terminated by a signal or stopped.

Notes:

- These macros are defined in <sys/wait.h> on POSIX-compliant systems.

- The status value is an int, and the interpretation of its bits is implementation-defined but standardized in terms of these macros.

- Windows and some non-POSIX environments may provide different mechanisms for child-process termination status.

See also: wait, waitpid, WIFSIGNALED, WIFSTOPPED, WEXITSTATUS, WTERMSIG.