WIFCONTINUED

WIFCONTINUED is a macro used in conjunction with the wait family of system calls (such as waitpid and wait) to inspect the status value returned for a child process. It indicates whether a child process has been continued after being stopped by job control signals.

The macro evaluates to a nonzero value when the status reports that a previously stopped child has been continued (for example, via the SIGCONT signal). It is meaningful only when the wait operation was asked to report continued processes, typically by passing the WCONTINUED option to waitpid or waitid. In a typical status-check sequence, WIFCONTINUED is tested alongside other macros such as WIFEXITED, WIFSIGNALED, and WIFSTOPPED.

Usage typically appears as part of a loop that handles all possible child state transitions. For example, after calling waitpid with the appropriate options, code may check WIFEXITED to handle normal termination, WIFSIGNALED for termination by a signal, WIFSTOPPED for a stop, and WIFCONTINUED for a continuation after a stop. The WCONTINUED flag must be supplied to the wait call to ensure continued-status events are delivered on systems that support job control.

Portability notes: WIFCONTINUED is part of the POSIX specification and is widely implemented on modern Unix-like systems. On platforms lacking job control or without requesting continued statuses, the macro may not report true outcomes. It reflects a transition from a stopped state to running due to SIGCONT, and does not indicate process completion or termination.

See also: WIFEXITED, WEXITSTATUS, WIFSIGNALED, WTERMSIG, WIFSTOPPED, WSTOPSIG, WCONTINUED, waitpid, wait.