'\"
'\" Copyright (c) 1997 Maorong Zou
'\" 
.TH EZ_RegisterMessageHandler 3 "" EZWGL "EZWGL Functions"
.BS
.SH NAME
EZ_RegisterMessageHandler, EZ_DeleteMessageHandler \- add/delete a message handler

.SH SYNOPSIS
.nf
.B #include <EZ.h>
.sp
typedef struct {
  Atom       messageType;    /* message type   */
  int        messageLength;  /* message length */
  char       *message;       /* the message    */
  int        messageId;      /* message Id     */
  int        replyId;        /* if request, the message id to reply */
  int        isReply;        /* flag whether the message is a reply */
  Window     sender;         /* sender's communication window id  */
  Atom       senderClass;    /* sender's class name */
  Atom       senderInstance; /* sender's instance name */
  int        senderIsSelf;   /* is message originated from the myself? */
} EZ_Message;
.sp
typedef void (*EZ_MessageHandler)(EZ_Message *msgIn, void *client_data);
.sp
.BI "void EZ_RegisterMessageHandler(Atom " type ", int " messageId ", void "*client_data,
.BI "                          EZ_MessageHandler " handler ", int " timeout, 
.BI "                          EZ_CallBack "timeoutCB ", void " cdata )
.sp
.BI "void EZ_DeleteMessageHandler(Atom " type ", int " messageId ", void "*client_data,
.BI "                          EZ_MessageHandler " handler)


.SH ARGUMENTS
\fIhandler\fR  Specifies a message handler.
.sp
\fIclient_data\fR  Specifies an application data to be passed to the handler.
.sp
\fImessageId\fR Specifies a serial number. Serial number is local to each
application so the sender has to keep track of it.
.sp
\fItimeout\fR Specifies the life span of this handler, in seconds. The handler
will be deleted after the specified number of seconds elapses. If zero or negative, 
the handler will have an infinite life span.
.sp
\fItimeoutCB\fR Specifies a procedure to execute when the handler expires.
.sp
\fIcdata\fR Specifies a client data to be passed to \fItimeoutCB\fR.

.SH DESCRIPTION
.PP
\fBEZ_RegisterMessageHandler\fR registers a message handler with EZWGL. The
message handler will be invoked when a messages with the specified type and
ID arrives. If \fitimeout\fR>0, the handler will expire in the specified
number of seconds; when it expires, it executes \fItimeoutCB\fR if supplied.

.PP
\fBEZ_DeleteMessageHandler\fR deletes the registered message handler
that matches the specification.

.SH "SEE ALSO"
EZ_SetDefaultMessageHandler(3), EZ_BroadcastMessage(3), EZ_ReplyMessage(3)
.br