The SetUserAgentInfo API procedure can be used by application software to modify the default SIP "User-Agent:" header that gets transmitted with every SIP message. The user agent header that is present in transmitted SIP messages consists of three parts of information - a product name, a version string and a user defined comment.

Namespace:  LanScape
Assembly:  LMEVoipManaged (in LMEVoipManaged.dll) Version: 6.0.5226.26700


public VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SetUserAgentInfo(
	string UserAgentProduct,
	string UserAgentVersion,
	string UserAgentComment
Visual Basic (Declaration)
Public Function SetUserAgentInfo ( _
	UserAgentProduct As String, _
	UserAgentVersion As String, _
	UserAgentComment As String _
Visual C++
VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SetUserAgentInfo(
	String^ UserAgentProduct, 
	String^ UserAgentVersion, 
	String^ UserAgentComment
public VoipMediaEngine..::.TELEPHONY_RETURN_VALUE SetUserAgentInfo(
	String UserAgentProduct,
	String UserAgentVersion,
	String UserAgentComment


Type: System..::.String
The product name of your VOIP application.
Type: System..::.String
The version string of your VOIP application.
Type: System..::.String
A user defined comment string.

Return Value

If the function succeeds, the return value will be SipSuccess.

If the function fails, the return value will be one of the following values as specified by the VoipMediaEngine..::.TELEPHONY_RETURN_VALUE data type.

Return ValueDescription
This value is returned by telephony API procedures to indicate general API failure. This error value is used as a "catch all error". If you receive this error, check to make sure that all parameters specified in the API procedure call are correct. Particularly, verify that pointers to memory regions are valid. This error return value is only used if a mapping to another specific error value does not exist.

(API return value)

One of the telephony API procedures was called by application software and was passed a pointer to an invalid memory address. Normally this error will occur when application software passes NULL pointer values to the telephony API. For managed code applications, you should never see this error unless your process space has exhausted memory.

(API return value)


As an example of how to call this API procedure, if you specified the product, version and comment strings to be "LanScape Utility Softphone", "v5.10.0.5" and "" respectfully, the SIP "User-Agent:" header that will be placed into each transmitted SIP message would be:

        User-Agent: LanScape Utility Softphone/v5.10.0.5 (

See Also