~mdw / qmail / blame
| Commit | Line | Data |
|---|---|---|
| 2117e02e MW |
1 | .TH wait 3 |
| 2 | .SH NAME | |
| 3 | wait \- check child process status | |
| 4 | .SH SYNTAX | |
| 5 | .B #include <wait.h> | |
| 6 | ||
| 7 | int \fBwait_nohang\fP(&\fIwstat\fR); | |
| 8 | .br | |
| 9 | int \fBwait_stop\fP(&\fIwstat\fR); | |
| 10 | .br | |
| 11 | int \fBwait_stopnohang\fP(&\fIwstat\fR); | |
| 12 | .br | |
| 13 | int \fBwait_pid\fP(&\fIwstat\fR,\fIpid\fR); | |
| 14 | ||
| 15 | int \fBwait_exitcode\fP(\fIwstat\fR); | |
| 16 | .br | |
| 17 | int \fBwait_crashed\fP(\fIwstat\fR); | |
| 18 | .br | |
| 19 | int \fBwait_stopped\fP(\fIwstat\fR); | |
| 20 | .br | |
| 21 | int \fBwait_stopsig\fP(\fIwstat\fR); | |
| 22 | ||
| 23 | int \fIpid\fR; | |
| 24 | .br | |
| 25 | int \fIwstat\fR; | |
| 26 | .SH DESCRIPTION | |
| 27 | .B wait_nohang | |
| 28 | looks for zombies (child processes that have exited). | |
| 29 | If it sees a zombie, | |
| 30 | it eliminates the zombie, | |
| 31 | puts the zombie's exit status into | |
| 32 | .IR wstat , | |
| 33 | and returns the zombie's process ID. | |
| 34 | If there are several zombies, | |
| 35 | .B wait_nohang | |
| 36 | picks one. | |
| 37 | If there are children but no zombies, | |
| 38 | .B wait_nohang | |
| 39 | returns 0. | |
| 40 | If there are no children, | |
| 41 | .B wait_nohang | |
| 42 | returns -1, | |
| 43 | setting | |
| 44 | .B errno | |
| 45 | appropriately. | |
| 46 | ||
| 47 | .B wait_stopnohang | |
| 48 | is similar to | |
| 49 | .BR wait_nohang , | |
| 50 | but it also looks for children that have stopped. | |
| 51 | ||
| 52 | .B wait_stop | |
| 53 | is similar to | |
| 54 | .BR wait_stopnohang , | |
| 55 | but if there are children it will pause waiting for one of them | |
| 56 | to stop or exit. | |
| 57 | ||
| 58 | .B wait_pid | |
| 59 | waits for child process | |
| 60 | .I pid | |
| 61 | to exit. | |
| 62 | It eliminates any zombie that shows up in the meantime, | |
| 63 | discarding the exit status. | |
| 64 | ||
| 65 | .B wait_stop | |
| 66 | and | |
| 67 | .B wait_pid | |
| 68 | retry upon | |
| 69 | .BR error_intr . | |
| 70 | .SH "STATUS PARSING" | |
| 71 | If the child stopped, | |
| 72 | .B wait_stopped | |
| 73 | is nonzero; | |
| 74 | .B wait_stopsig | |
| 75 | is the signal that caused the child to stop. | |
| 76 | ||
| 77 | If the child exited by crashing, | |
| 78 | .B wait_stopped | |
| 79 | is zero; | |
| 80 | .B wait_crashed | |
| 81 | is nonzero. | |
| 82 | ||
| 83 | If the child exited normally, | |
| 84 | .B wait_stopped | |
| 85 | is zero; | |
| 86 | .B wait_crashed | |
| 87 | is zero; | |
| 88 | and | |
| 89 | .B wait_exitcode | |
| 90 | is the child's exit code. | |
| 91 | .SH "SEE ALSO" | |
| 92 | wait(2), | |
| 93 | error(3) |