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Diffstat (limited to 'xpa/man/man3/xpamainloop.3')
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diff --git a/xpa/man/man3/xpamainloop.3 b/xpa/man/man3/xpamainloop.3 new file mode 100644 index 0000000..ff01099 --- /dev/null +++ b/xpa/man/man3/xpamainloop.3 @@ -0,0 +1,214 @@ +.\" Automatically generated by Pod::Man 2.22 (Pod::Simple 3.13) +.\" +.\" Standard preamble: +.\" ======================================================================== +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.de Vb \" Begin verbatim text +.ft CW +.nf +.ne \\$1 +.. +.de Ve \" End verbatim text +.ft R +.fi +.. +.\" Set up some character translations and predefined strings. \*(-- will +.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left +.\" double quote, and \*(R" will give a right double quote. \*(C+ will +.\" give a nicer C++. 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Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.if n .ad l +.nh +.SH "NAME" +\&\fBXPAMainLoop: optional main loop for \s-1XPA\s0\fR +.SH "SYNOPSIS" +.IX Header "SYNOPSIS" +.Vb 1 +\& #include <xpa.h> +\& +\& void XPAMainLoop(); +.Ve +.SH "DESCRIPTION" +.IX Header "DESCRIPTION" +Once \s-1XPA\s0 access points have been defined, a program must enter an +event loop to watch for requests from external programs. This can be +done in a variety of ways, depending on whether the event loop is +processing events other than \s-1XPA\s0 events. In cases where there are no +non-XPA events to be processed, the program can simply call the +\&\fIXPAMainLoop()\fR event loop. This loop is implemented essentially as +follows (error checking is simplified in this example): +.PP +.Vb 8 +\& FD_ZERO(&readfds); +\& while( XPAAddSelect(NULL, &readfds) ){ +\& if( sgot = select(swidth, &readfds, NULL, NULL, NULL) >0 ) +\& XPAProcessSelect(&readfds, 0); +\& else +\& break; +\& FD_ZERO(&readfds); +\& } +.Ve +.PP +The \fIXPAAddSelect()\fR routine sets up the \fIselect()\fR readfds variable so +that \fIselect()\fR will wait for I/O on all the active \s-1XPA\s0 channels. It +returns the number of XPAs that are active; the loop will end when +there are no active XPAs. The standard \fIselect()\fR routine is called to +wait for an external I/O request. Since no timeout struct is passed +in argument 5, the \fIselect()\fR call hangs until there is an external +request. When an external I/O request is made, the \fIXPAProcessSelect()\fR +routine is executed to process the pending requests. In this routine, +the maxreq value determines how many requests will be processed: if +maxreq <=0, then all currently pending requests will be processed. +Otherwise, up to maxreq requests will be processed. (The most usual +values for maxreq is 0 to process all requests.) +.PP +If a program has its own Unix \fIselect()\fR loop, then \s-1XPA\s0 access points can +be added to it by using a variation of the standard XPAMainLoop: +.PP +.Vb 7 +\& XPAAddSelect(xpa, &readfds); +\& [app\-specific ...] +\& if( select(width, &readfds, ...) ){ +\& XPAProcessSelect(&readfds, maxreq); +\& [app\-specific ...] +\& FD_ZERO(&readfds); +\& } +.Ve +.PP +\&\fIXPAAddSelect()\fR is called before \fIselect()\fR to add the access points. +If the first argument is \s-1NULL\s0, then all active \s-1XPA\s0 access points +are added. Otherwise only the specified access point is added. +After \fIselect()\fR is called, the \fIXPAProcessSelect()\fR routine can be called +to process \s-1XPA\s0 requests. Once again, the maxreq value determines how +many requests will be processed: if maxreq <=0, then all currently +pending requests will be processed. Otherwise, up to maxreq requests +will be processed. +.PP +\&\s-1XPA\s0 access points can be added to +Xt event loops (using \fIXtAppMainLoop()\fR) +and +Tcl/Tk event loops (using vwait and the Tk loop). +When using \s-1XPA\s0 with these event loops, you only need to call: +.PP +int XPAXtAddInput(XtAppContext app, \s-1XPA\s0 xpa) +.PP +or +.PP +.Vb 1 +\& int XPATclAddInput(XPA xpa) +.Ve +.PP +respectively before entering the loop. +.SH "SEE ALSO" +.IX Header "SEE ALSO" +See xpa(n) for a list of \s-1XPA\s0 help pages |