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5b62e993 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) |