# Requesting capability information

Use nccSendCapabilityQuery to send a SIP OPTIONS message when requesting capability information from the remote end. The nccSendCapabilityQuery parameters specify a line handle (linehd) and a SIP IE list to use for building the OPTIONS method headers (sipIEs).

#### Prototype

DWORD nccSendCapabilityQuery( CTAHD linehd, void * sipIEs)

Argument | Description
linehd | Line handle used to open the NCC service instance.
sipIEs | NULL or pointer to a buffer containing SIP IEs.

#### SIP capability information structure

The following table lists the optional and required information elements (IEs):

Information element (IE) | Required or optional | Description
SIP_IE_TO_FULL_ADDRESS | Required | SIP URI of the remote user.
SIP_IE_FROM_FULL_ADDRESS | Required | SIP URI of the local user.
SIP_IE_REQUEST_URI | Required | Address for requested URI.
SIP_IE_OTHER_HEADER | Required | Specifies the Accept header.
SIP_IE_CONTACT_ADDRESS | Optional | Contact address.

#### Example

The following example illustrates how to request capability information using nccSendCapabilityQuery:

DWORD b[2048];
NCC_SIP_INFO *ie;
NCC_SIP_INFO_INIT ( b, &ie );
NCC_SIP_INFO_ADD_STR ( b, &ie, SIP_IE_TO_FULL_ADDRESS, sip.to );
NCC_SIP_INFO_ADD_STR ( b, &ie, SIP_IE_FROM_FULL_ADDRESS, sip.from );
NCC_SIP_INFO_ADD_STR ( b, &ie, SIP_IE_REQUEST_URI, sip.requestUri );
NCC_SIP_INFO_ADD_STR ( b, &ie, SIP_IE_OTHER_HEADER, "Accept:application/sdp" );
NCC_SIP_INFO_ADD_STR ( b, &ie, SIP_IE_CONTACT_ADDRESS, sip.contact );
ret = nccSendCapabilityQuery( ctahd, b);