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+'\"
+'\" Copyright (c) 1989-1993 The Regents of the University of California.
+'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
+'\"
+'\" See the file "license.terms" for information on usage and redistribution
+'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+'\" 
+'\" SCCS: @(#) DetachPids.3 1.15 96/08/26 12:59:44
+'\" 
+.so man.macros
+.TH Tcl_DetachPids 3 "" Tcl "Tcl Library Procedures"
+.BS
+.SH NAME
+Tcl_DetachPids, Tcl_ReapDetachedProcs \- manage child processes in background
+.SH SYNOPSIS
+.nf
+\fB#include <tcl.h>\fR
+.sp
+\fBTcl_DetachPids\fR(\fInumPids, pidPtr\fR)
+.sp
+\fBTcl_ReapDetachedProcs\fR()
+.SH ARGUMENTS
+.AS int *statusPtr
+.AP int numPids in
+Number of process ids contained in the array pointed to by \fIpidPtr\fR.
+.AP int *pidPtr in
+Address of array containing \fInumPids\fR process ids.
+.BE
+
+.SH DESCRIPTION
+.PP
+\fBTcl_DetachPids\fR and \fBTcl_ReapDetachedProcs\fR provide a
+mechanism for managing subprocesses that are running in background.
+These procedures are needed because the parent of a process must
+eventually invoke the \fBwaitpid\fR kernel call (or one of a few other
+similar kernel calls) to wait for the child to exit.  Until the
+parent waits for the child, the child's state cannot be completely
+reclaimed by the system.  If a parent continually creates children
+and doesn't wait on them, the system's process table will eventually
+overflow, even if all the children have exited.
+.PP
+\fBTcl_DetachPids\fR may be called to ask Tcl to take responsibility
+for one or more processes whose process ids are contained in the
+\fIpidPtr\fR array passed as argument.  The caller presumably
+has started these processes running in background and doesn't
+want to have to deal with them again.
+.PP
+\fBTcl_ReapDetachedProcs\fR invokes the \fBwaitpid\fR kernel call
+on each of the background processes so that its state can be cleaned
+up if it has exited.  If the process hasn't exited yet,
+\fBTcl_ReapDetachedProcs\fR doesn't wait for it to exit;  it will check again
+the next time it is invoked.
+Tcl automatically calls \fBTcl_ReapDetachedProcs\fR each time the
+\fBexec\fR command is executed, so in most cases it isn't necessary
+for any code outside of Tcl to invoke \fBTcl_ReapDetachedProcs\fR.
+However, if you call \fBTcl_DetachPids\fR in situations where the
+\fBexec\fR command may never get executed, you may wish to call
+\fBTcl_ReapDetachedProcs\fR from time to time so that background
+processes can be cleaned up.
+
+.SH KEYWORDS
+background, child, detach, process, wait