Peter Howkins
230 lines
8.8 KiB
Plaintext
230 lines
8.8 KiB
Plaintext
<!-- $XConsortium: load.sgm /main/6 1996/09/08 20:22:56 rws $ -->
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<!-- (c) Copyright 1995 Digital Equipment Corporation. -->
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<!-- (c) Copyright 1995 Hewlett-Packard Company. -->
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<!-- (c) Copyright 1995 International Business Machines Corp. -->
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<!-- (c) Copyright 1995 Sun Microsystems, Inc. -->
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<!-- (c) Copyright 1995 Novell, Inc. -->
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<!-- (c) Copyright 1995 FUJITSU LIMITED. -->
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<!-- (c) Copyright 1995 Hitachi. -->
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<![ %CDE.C.CDE; [<RefEntry Id="CDEMX.XCDI.MAN270.rsml.1">]]>
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<![ %CDE.C.XO; [<RefEntry Id="XCDI.MAN270.rsml.1">]]>
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<RefMeta>
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<RefEntryTitle>ttmedia_load</RefEntryTitle>
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<ManVolNum>library call</ManVolNum>
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</RefMeta>
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<RefNameDiv>
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<RefName><Function>ttmedia_load</Function></RefName>
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<RefPurpose>send a Display, Edit or Compose request
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</RefPurpose>
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</RefNameDiv>
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<!-- $XConsortium: load.sgm /main/6 1996/09/08 20:22:56 rws $-->
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<!-- CDE Common Source Format, Version 1.0.0-->
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<!-- (c) Copyright 1993, 1994, 1995 Hewlett-Packard Company-->
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<!-- (c) Copyright 1993, 1994, 1995 International Business Machines Corp.-->
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<!-- (c) Copyright 1993, 1994, 1995 Sun Microsystems, Inc.-->
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<!-- (c) Copyright 1993, 1994, 1995 Novell, Inc.-->
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<RefSynopsisDiv>
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<FuncSynopsis Remap="ANSI">
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<FuncSynopsisInfo>#include <Tt/tttk.h>
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</FuncSynopsisInfo>
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<FuncDef>Tt_message <Function>ttmedia_load</Function></FuncDef>
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<ParamDef>Tt_message <Parameter>context</Parameter></ParamDef>
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<ParamDef>Ttmedia_load_msg_cb <Parameter>cb</Parameter></ParamDef>
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<ParamDef>void *<Parameter>clientdata</Parameter></ParamDef>
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<ParamDef>Tttk_op <Parameter>op</Parameter></ParamDef>
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<ParamDef>const char *<Parameter>media_type</Parameter></ParamDef>
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<ParamDef>const unsigned char *<Parameter>contents</Parameter></ParamDef>
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<ParamDef>int <Parameter>len</Parameter></ParamDef>
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<ParamDef>const char *<Parameter>file</Parameter></ParamDef>
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<ParamDef>const char *<Parameter>docname</Parameter></ParamDef>
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<ParamDef>int <Parameter>send</Parameter></ParamDef>
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</FuncSynopsis>
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</RefSynopsisDiv>
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<RefSect1>
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<Title>DESCRIPTION</Title>
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<Para>The
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<Function>ttmedia_load</Function> function
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is used to create and optionally send a Media Exchange request
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to display, edit or compose a document.
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</Para>
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<Para>The
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<Emphasis>cb</Emphasis> argument will be passed
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<Emphasis>clientdata</Emphasis> when the reply is received, or when intermediate versions
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of the document are checkpointed through
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<Symbol Role="Message">Deposit</Symbol> requests.
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The
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<Symbol Role="Variable">op</Symbol> argument must be one of
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<SystemItem Class="Constant">TTME_DISPLAY</SystemItem>, <SystemItem Class="Constant">TTME_EDIT</SystemItem> or
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<SystemItem Class="Constant">TTME_COMPOSE</SystemItem>. The
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<Emphasis>media_type</Emphasis> argument names the data format of the document, and is usually the
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primary determinant of which application will be chosen to
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handle the request.
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The
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<Emphasis>contents</Emphasis> and
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<Emphasis>len</Emphasis> arguments specify the document; if they are
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<SystemItem Class="Constant">NULL</SystemItem> and zero, respectively, and
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<Symbol Role="Variable">file</Symbol> is not
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<SystemItem Class="Constant">NULL</SystemItem>, then the document is assumed to be contained in
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<Symbol Role="Variable">file</Symbol>. If
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<Emphasis>docname</Emphasis> is not
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<SystemItem Class="Constant">NULL</SystemItem>, then
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<Function>ttmedia_load</Function> uses it as the title of the document.
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If
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<Emphasis>send</Emphasis> is True, the message is sent before being returned.
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</Para>
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<Para>The
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<Symbol Role="Variable">context</Symbol> argument describes the environment to use.
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If
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<Symbol Role="Variable">context</Symbol> is not zero, messages created by
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<Function>ttmedia_load</Function> inherit from
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<Symbol Role="Variable">context</Symbol> all contexts whose slotname begins with the characters
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<SystemItem Class="Constant">ENV_</SystemItem>.</Para>
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<Para>The
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<StructName Role="typedef">Ttmedia_load_msg_cb</StructName> argument is a callback defined as:
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</Para>
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<InformalExample Remap="indent">
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<ProgramListing>Tt_message (*Ttmedia_load_msg_cb)(Tt_message <Emphasis>msg</Emphasis>,
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void *<Emphasis>clientdata</Emphasis>),
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Tttk_op <Symbol Role="Variable">op</Symbol>,
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unsigned char *<Emphasis>contents</Emphasis>,
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int <Emphasis>len</Emphasis>,
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char *<Symbol Role="Variable">file</Symbol>);
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</ProgramListing>
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</InformalExample>
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<Para>The
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<Emphasis>msg</Emphasis> argument is the
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reply to the load request, or a
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<Symbol Role="Message">Deposit</Symbol> request with a
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<Emphasis>messageID</Emphasis> argument naming the identifier (see
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&cdeman.tt.message.id;) of the load request.
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In the latter case, the client
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program becomes responsible for either failing or replying
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to the request.
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In either case,
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<Emphasis>msg</Emphasis> should be destroyed after being processed.
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</Para>
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<Para>The
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<Symbol Role="Variable">op</Symbol> argument is the
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op of
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<Emphasis>msg</Emphasis>. It must be either
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<SystemItem Class="Constant">TTME_DEPOSIT</SystemItem> or the
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<Symbol Role="Variable">op</Symbol> passed to
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&cdeman.ttmedia.load;.</Para>
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<Para>The
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<Emphasis>contents</Emphasis>, <Emphasis>len</Emphasis> and
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<Symbol Role="Variable">file</Symbol> arguments represent the
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contents of the arriving document.
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If
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<Emphasis>len</Emphasis> is zero, then the document is contained in
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<Symbol Role="Variable">file</Symbol>. If
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<Emphasis>contents</Emphasis> or
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<Symbol Role="Variable">file</Symbol> are non-
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<SystemItem Class="Constant">NULL</SystemItem>, they can be freed using
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<Function>tt_free</Function>.</Para>
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<Para>The
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<Emphasis>clientdata</Emphasis> argument is the
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<Emphasis>clientdata</Emphasis> passed to
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<Function>ttmedia_load</Function>.</Para>
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</RefSect1>
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<RefSect1>
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<Title>RETURN VALUE</Title>
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<Para>Upon successful completion, the
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<Function>ttmedia_load</Function> function returns the request it was asked to build;
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otherwise, it returns an error pointer.
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The application can use
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&cdeman.tt.ptr.error; to extract one of the following
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<StructName Role="typedef">Tt_status</StructName> values from the returned handle:
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</Para>
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<VariableList>
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<VarListEntry>
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<Term>TT_ERR_NOMEM</Term>
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<ListItem>
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<Para>There is insufficient memory available to perform the function.
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</Para>
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</ListItem>
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</VarListEntry>
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<VarListEntry>
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<Term>TT_ERR_NOMP</Term>
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<ListItem>
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<Para>The
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&cdeman.ttsession; process is not running and the ToolTalk service cannot restart it.
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</Para>
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</ListItem>
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</VarListEntry>
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<VarListEntry>
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<Term>TT_ERR_OVERFLOW</Term>
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<ListItem>
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<Para>The ToolTalk service has more active messages than it can handle.
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(The maximum number of active messages is
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implementation specific, but is at least 2000.)
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</Para>
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</ListItem>
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</VarListEntry>
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<VarListEntry>
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<Term>TT_ERR_PROCID</Term>
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<ListItem>
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<Para>The specified process identifier is out of date or invalid.
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</Para>
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</ListItem>
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</VarListEntry>
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</VariableList>
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</RefSect1>
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<RefSect1>
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<Title>APPLICATION USAGE</Title>
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<Para>After the request created by
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<Function>ttmedia_load</Function> is sent, the application will probably want to use
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<Function>ttdt_subcontract_manage</Function> immediately afterwards to manage the standard interactions with the
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handler of the request.
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</Para>
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<Para>A
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<StructName Role="typedef">Ttmedia_load_msg_cb</StructName> callback should return
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<SystemItem Class="Constant">NULL</SystemItem> if it processes
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<Emphasis>msg</Emphasis> successfully, or a
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<Function>tt_error_pointer</Function> cast to
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<StructName Role="typedef">Tt_message</StructName> if processing results in an error.
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It should return the
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<Emphasis>msg</Emphasis> if it does not consume it, in which case
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the ToolTalk service
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will pass
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<SystemItem Class="Constant">TT_CALLBACK_CONTINUE</SystemItem> down the call stack, so that
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<Emphasis>msg</Emphasis> will be offered to other callbacks or (more likely) be returned
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from
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&cdeman.tt.message.receive;. Applications will rarely want
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<Emphasis>msg</Emphasis> to get processed by other callbacks or in the main event loop.
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</Para>
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</RefSect1>
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<RefSect1>
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<Title>EXAMPLES</Title>
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<Para>This is the typical algorithm of a
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<StructName Role="typedef">Ttmedia_load_msg_cb</StructName>:</Para>
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<InformalExample Remap="indent">
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<ProgramListing>Tt_message
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myLoadMsgCB(Tt_message msg,
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void *clientData,
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Tttk_op op,
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unsigned char *contents,
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int len,
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char *file)
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{
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if (len > 0) {
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/* Replace data with len bytes in contents */
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} else if (file != 0) {
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/* Replace data with data read from file */
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}
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if (op == TTME_DEPOSIT) {
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tt_message_reply(msg);
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}
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tttk_message_destroy(msg);
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return 0;
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}
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</ProgramListing>
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</InformalExample>
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</RefSect1>
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<RefSect1>
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<Title>SEE ALSO</Title>
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<Para>&cdeman.Tt.tttk.h;, &cdeman.ttmedia.load.reply;, &cdeman.ttmedia.ptype.declare;, &cdeman.ttmedia.Deposit;, &cdeman.tt.free;, &cdeman.tt.message.receive;.</Para>
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</RefSect1>
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</RefEntry>
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<!--fickle 1.12 mancsf-to-docbook 1.2 08/07/95 23:18:47-->
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