flux_child_watcher_create(3)¶
SYNOPSIS¶
#include <flux/core.h>
typedef void (*flux_watcher_f)(flux_reactor_t *r,
flux_watcher_t *w,
int revents, void *arg);
flux_watcher_t *flux_child_watcher_create (flux_reactor_t *r,
int pid, bool trace,
flux_watcher_f cb, void *arg);
int flux_child_watcher_get_rpid (flux_watcher_t *w);
int flux_child_watcher_get_rstatus (flux_watcher_t *w);
DESCRIPTION¶
flux_child_watcher_create() creates a reactor watcher that
monitors state transitions of child processes. If trace is false,
only child termination will trigger an event; otherwise, stop and start
events may be generated.
The callback revents argument should be ignored.
The process id that had a transition may be obtained by calling
flux_child_watcher_get_rpid().
The status value returned by waitpid(2) may be obtained by calling
flux_child_watcher_get_rstatus().
Only a Flux reactor created with the FLUX_REACTOR_SIGCHLD flag can be used with child watchers, as the reactor must register a SIGCHLD signal watcher before any processes are spawned. Only one reactor instance per program may be created with this capability.
RETURN VALUE¶
flux_child_watcher_create() returns a flux_watcher_t object on success. On error, NULL is returned, and errno is set appropriately.
ERRORS¶
- ENOMEM
Out of memory.
- EINVAL
Reactor was not created with FLUX_REACTOR_SIGCHLD.