WIFSIGNALED

WIFSIGNALED is a macro used in POSIX-compliant systems to analyze the termination status of a child process as reported by wait, waitpid, or waitid. It evaluates the status value returned by these wait system calls and indicates whether the child process ended because it received an uncaught signal.

When WIFSIGNALED(status) is true, the child process did not exit normally but was terminated by a signal. In this case, the WTERMSIG(status) macro can be used to obtain the number of the terminating signal. The signal number corresponds to the conventional signal identifiers defined in signal.h, such as SIGKILL or SIGTERM.

WIFSIGNALED is one of several macros used to interpret wait status values. Others include WIFEXITED, which indicates normal termination, and WIFSTOPPED, which indicates the process was stopped by a signal. When WIFEXITED(status) is true, WEXITSTATUS(status) yields the process’s exit code. When WIFSTOPPED(status) is true, WSTOPSIG(status) yields the signal that stopped the process.

Example usage in C after a wait call:

if (WIFSIGNALED(status)) {

int sig = WTERMSIG(status);

// handle termination by signal sig

}

Portability and scope: WIFSIGNALED and related macros are defined by the POSIX standard and are available on POSIX-compliant systems (commonly via <sys/wait.h>). They are not applicable on non-POSIX platforms without equivalent wait status facilities.

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