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);
Link with -lflux-core.
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.
RESOURCES
Flux: http://flux-framework.org
Flux RFC: https://flux-framework.readthedocs.io/projects/flux-rfc