.TH wait 3

.SH NAME

wait \- check child process status

.SH SYNTAX

.B #include <wait.h>

int \fBwait_nohang\fP(&\fIwstat\fR);

.br

int \fBwait_stop\fP(&\fIwstat\fR);

.br

int \fBwait_stopnohang\fP(&\fIwstat\fR);

.br

int \fBwait_pid\fP(&\fIwstat\fR,\fIpid\fR);

int \fBwait_exitcode\fP(\fIwstat\fR);

.br

int \fBwait_crashed\fP(\fIwstat\fR);

.br

int \fBwait_stopped\fP(\fIwstat\fR);

.br

int \fBwait_stopsig\fP(\fIwstat\fR);

int \fIpid\fR;

.br

int \fIwstat\fR;

.SH DESCRIPTION

.B wait_nohang

looks for zombies (child processes that have exited).

If it sees a zombie,

it eliminates the zombie,

puts the zombie's exit status into

.IR wstat ,

and returns the zombie's process ID.

If there are several zombies,

.B wait_nohang

picks one.

If there are children but no zombies,

.B wait_nohang

returns 0.

If there are no children,

.B wait_nohang

returns -1,

setting

.B errno

appropriately.

.B wait_stopnohang

is similar to

.BR wait_nohang ,

but it also looks for children that have stopped.

.B wait_stop

is similar to

.BR wait_stopnohang ,

but if there are children it will pause waiting for one of them

to stop or exit.

.B wait_pid

waits for child process

.I pid

to exit.

It eliminates any zombie that shows up in the meantime,

discarding the exit status.

.B wait_stop

and

.B wait_pid

retry upon

.BR error_intr .

.SH "STATUS PARSING"

If the child stopped,

.B wait_stopped

is nonzero;

.B wait_stopsig

is the signal that caused the child to stop.

If the child exited by crashing,

.B wait_stopped

is zero;

.B wait_crashed

is nonzero.

If the child exited normally,

.B wait_stopped

is zero;

.B wait_crashed

is zero;

and

.B wait_exitcode

is the child's exit code.

.SH "SEE ALSO"

wait(2),

error(3)