From 78e51a8c6678b6e3dff3d619aa786669f531f4bc Mon Sep 17 00:00:00 2001 From: rsc Date: Fri, 14 Jan 2005 03:45:44 +0000 Subject: checkpoint --- man/man3/wait.html | 170 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) create mode 100644 man/man3/wait.html (limited to 'man/man3/wait.html') diff --git a/man/man3/wait.html b/man/man3/wait.html new file mode 100644 index 00000000..84322bc2 --- /dev/null +++ b/man/man3/wait.html @@ -0,0 +1,170 @@ + +wait(3) - Plan 9 from User Space + + + + +
+
+
WAIT(3)WAIT(3) +
+
+

NAME
+ +
+ + await, awaitnohang, awaitfor, wait, waitnohang, waitfor, waitpid + – wait for a process to exit
+ +
+

SYNOPSIS
+ +
+ + #include <u.h>
+ #include <libc.h> +
+ + Waitmsg*    wait(void) +
+ + Waitmsg*    waitnohang(void) +
+ + Waitmsg*    waitfor(int pid) +
+ + int         waitpid(void) +
+ + int         await(char *s, int n) +
+ + int         awaitnohang(char *s, int n) +
+ + int         awaitfor(int pid, char *s, int n)
+ +
+

DESCRIPTION
+ +
+ + Wait causes a process to wait for any child process (see fork(2) + and rfork(3)) to exit. It returns a Waitmsg holding information + about the exited child. A Waitmsg has this structure:
+ +
+ + typedef
+ struct Waitmsg
+ {
+ +
+ + int pid;               /* of loved one */
+ ulong time[3];          /* of loved one & descendants */
+ char *msg;
+ +
+ } Waitmsg;
+ +
+ + +
+ Pid is the child’s process id. The time array contains the time + the child and its descendants spent in user code, the time spent + in system calls, and the child’s elapsed real time, all in units + of milliseconds. Msg contains the message that the child specified + in exits(3). For a normal exit, msg[0] is zero, otherwise msg + is the exit string prefixed by the process name, a blank, the + process id, and a colon. +
+ + If there are no more children to wait for, wait returns immediately, + with return value nil. +
+ + The Waitmsg structure is allocated by malloc(3) and should be + freed after use. For programs that only need the pid of the exiting + program, waitpid returns just the pid and discards the rest of + the information. +
+ + Waitnohang is like wait but does not block if there are no more + children to wait for. Instead it returns immediately and sets + errstr. +
+ + Waitfor is like wait but waits for a particular pid. +
+ + The underlying calls are await, awaitnohang, and awaitfor, which + fill in the n-byte buffer s with a textual representation of the + pid, times, and exit string. There is no terminal NUL. The return + value is the length, in bytes, of the data. +
+ + The filled-in buffer may be parsed (after appending a NUL) using + tokenize (see getfields(3)); the resulting fields are, in order, + pid, the three times, and the exit string, which will be '' for + normal exit. If the representation is longer than n bytes, it + is truncated but, if possible, properly formatted. The information + that + does not fit in the buffer is discarded, so a subsequent call + to await will return the information about the next exiting child, + not the remainder of the truncated message. In other words, each + call to await returns the information about one child, blocking + if necessary if no child has exited. If the calling process has + no + living children, await returns −1.
+ +
+

SOURCE
+ +
+ + /usr/local/plan9/src/lib9/wait.c +
+ + /usr/local/plan9/src/lib9/await.c
+ +
+

SEE ALSO
+ +
+ + rfork(3), exits(3),
+ +
+

DIAGNOSTICS
+ +
+ + These routines set errstr.
+ +
+

BUGS
+ +
+ + To avoid name conflicts with the underlying system, wait, waitpid, + and waitfor are preprocessor macros defined as p9wait, p9waitpid, + and p9waitfor; see intro(3).
+ +
+ +

 +
+
+ + +
+
+
+Space Glenda +
+
+ + -- cgit v1.2.3