<div class="content" name="NegotiateAPIVersion_Line" uuid="7c69dced-7bee-4ec8-a02e-f90b7afcfba6"><p>The NegotiateAPIVersion packet is transmitted from a TAPI <a href="489de77f-16d8-4c4f-939a-f795e8b42893#gt_60e0e1fa-66fe-41e1-b5e3-ceab97e53506" data-linktype="relative-path">client</a> to a TAPI <a href="489de77f-16d8-4c4f-939a-f795e8b42893#gt_434b0234-e970-4e8c-bdfa-e16a30d96703" data-linktype="relative-path">server</a> in a <a href="489de77f-16d8-4c4f-939a-f795e8b42893#gt_8a7f6700-8311-45bc-af10-82e10accd331" data-linktype="relative-path">remote procedure call</a>.
Sending this packet allows an application to negotiate a TAPI version to use.</p><table>
 <tbody><tr>
  <th><p><br/>0</p></th>
  <th><p><br/>1</p></th>
  <th><p><br/>2</p></th>
  <th><p><br/>3</p></th>
  <th><p><br/>4</p></th>
  <th><p><br/>5</p></th>
  <th><p><br/>6</p></th>
  <th><p><br/>7</p></th>
  <th><p><br/>8</p></th>
  <th><p><br/>9</p></th>
  <th><p>1<br/>0</p></th>
  <th><p><br/>1</p></th>
  <th><p><br/>2</p></th>
  <th><p><br/>3</p></th>
  <th><p><br/>4</p></th>
  <th><p><br/>5</p></th>
  <th><p><br/>6</p></th>
  <th><p><br/>7</p></th>
  <th><p><br/>8</p></th>
  <th><p><br/>9</p></th>
  <th><p>2<br/>0</p></th>
  <th><p><br/>1</p></th>
  <th><p><br/>2</p></th>
  <th><p><br/>3</p></th>
  <th><p><br/>4</p></th>
  <th><p><br/>5</p></th>
  <th><p><br/>6</p></th>
  <th><p><br/>7</p></th>
  <th><p><br/>8</p></th>
  <th><p><br/>9</p></th>
  <th><p>3<br/>0</p></th>
  <th><p><br/>1</p></th>
 </tr>
 <tr>
  <td colspan="32">Req_Func</td>
 </tr>
 <tr>
  <td colspan="32">Reserved1</td>
 </tr>
 <tr>
  <td colspan="32">hLineApp</td>
 </tr>
 <tr>
  <td colspan="32">dwDeviceID</td>
 </tr>
 <tr>
  <td colspan="32">dwVersion</td>
 </tr>
 <tr>
  <td colspan="32">dwVersionCurrent</td>
 </tr>
 <tr>
  <td colspan="32">dwNegotiatedVersion</td>
 </tr>
 <tr>
  <td colspan="32">ExtensionID</td>
 </tr>
 <tr>
  <td colspan="32">dwSize</td>
 </tr>
 <tr>
  <td colspan="32">Reserved2</td>
 </tr>
 <tr>
  <td colspan="32">Reserved3</td>
 </tr>
 <tr>
  <td colspan="32">Reserved4</td>
 </tr>
 <tr>
  <td colspan="32">Reserved5</td>
 </tr>
 <tr>
  <td colspan="32">Reserved6</td>
 </tr>
 <tr>
  <td colspan="32">Reserved7</td>
 </tr>
 <tr>
  <td colspan="32">VarData (16 bytes)</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
 <tr>
  <td colspan="32">...</td>
 </tr>
</tbody></table><p><b>Req_Func (4 bytes): </b>An unsigned 32-bit
integer. The identifier of the function that is invoked on the remote server.
This value MUST be set to 52.</p><dl>
<dd>
<p><b>Return Values</b></p>
</dd>
<dd>
<p>On completion of <a href="c28c36d0-579b-4e20-a100-f4e71012d5f8" data-linktype="relative-path">ClientRequest</a>, this field
contains the result of the encapsulated telephony request. A value of 0
indicates success, and a <a href="e0e8af90-24f1-4dbc-8d4e-01b8e4e7cb53" data-linktype="relative-path">LINEERR_Constants</a>
value indicates failure. The remote server MUST complete this call synchronously.</p>
</dd>
<dd>
<p>MUST return zero if the function succeeds or an
error number if an error occurs. Common return values are as follows:</p>
</dd>
<dd>
<table><thead>
  <tr>
   <th>
   <p>Name</p>
   </th>
   <th>
   <p>Value</p>
   </th>
  </tr>
 </thead><tbody><tr>
  <td>LINEERR_INCOMPATIBLEAPIVERSION</td>
  <td>0x8000000C</td>
 </tr><tr>
  <td>LINEERR_OPERATIONUNAVAIL</td>
  <td>0x80000049</td>
 </tr><tr>
  <td>LINEERR_NODRIVER</td>
  <td>0x80000043</td>
 </tr><tr>
  <td>LINEERR_OPERATIONFAILED</td>
  <td>0x80000048</td>
 </tr><tr>
  <td>LINEERR_NOMEM</td>
  <td>0x80000044</td>
 </tr><tr>
  <td>LINEERR_RESOURCEUNAVAIL</td>
  <td>0x8000004B</td>
 </tr></tbody></table>
</dd></dl><p><b>Reserved1 (4 bytes): </b>An unsigned 32-bit
integer. MUST be set to zero when sent and MUST be ignored on receipt. </p><p><b>hLineApp (4 bytes): </b>An <a href="c12b4793-3220-4f9e-aa86-8edd3e7020d4" data-linktype="relative-path">HLINEAPP</a>. A handle to the
client application&#39;s registration with TAPI. This field MUST have been obtained
by sending the <a href="9d8eb7cd-3245-4e44-97e0-42f7b89c9424" data-linktype="relative-path">Initialize</a>
packet.</p><p><b>dwDeviceID (4 bytes): </b>An unsigned 32-bit
integer. Identifies the line device for which the interface version negotiation
is to be performed. A valid value of dwDeviceID is in the range 0 to dwNumDevs
– 1. The client obtains dwNumDevs by sending a Initialize packet to the remote
server.</p><p><b>dwVersion (4 bytes): </b>An unsigned 32-bit
integer. The earliest TAPI version with which the application is compliant.</p><p><b>dwVersionCurrent (4 bytes): </b>An unsigned 32-bit
integer. The latest TAPI version with which the application is compliant.</p><p><b>dwNegotiatedVersion (4 bytes): </b>An unsigned
32-bit integer. Set to TAPI_NO_DATA (0xFFFFFFFF). Upon successful completion of
the request, this field will contain the TAPI version number that was
negotiated.</p><p><b>ExtensionID (4 bytes): </b>An unsigned 32-bit
integer. Set to TAPI_NO_DATA (0xFFFFFFFF). Upon successful completion of the
request, this field MUST contain the offset, in bytes, in the <b>VarData</b>
field of a <a href="175fc696-817b-46eb-9ef0-fda89830d969" data-linktype="relative-path">LINEEXTENSIONID</a>
packet that indicates the identifier of the provider-specific extensions.</p><p><b>dwSize (4 bytes): </b>An unsigned 32-bit integer.
The size, in bytes, of the packet that is indicated in the <b>ExtensionID</b>
field.</p><p><b>Reserved2 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved3 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved4 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved5 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved6 (4 bytes): </b>An unsigned 32-bit integer.
This field is used for padding and MUST be ignored on receipt. It can be any
value.</p><p><b>Reserved7 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>VarData (16 bytes): </b>Present on successful
completion of the request. Contains a LINEEXTENSIONID packet.</p><dl>
<dd>
<p>The contents of this field are DWORD aligned.</p>
</dd></dl></div>