# nccQueryCapability

Queries the capabilities of the signaling protocol.

#### Prototype

DWORD nccQueryCapability ( CTAHD linehd, NCC_PROT_CAP *protcap, unsigned size )

Argument | Description
linehd | Context handle used to open the NCC service instance.
protcap | A pointer to an NCC_PROT_CAP structure to hold returned protocol capability information. typedef struct { DWORD size; DWORD capabilitymask; } NCC_PROT_CAP; See the Details section for field descriptions.
size | The size of NCC_PROT_CAP structure.

#### Return values

Return value | Description
SUCCESS |
CTAERR_INVALID_HANDLE | The NCC service is not open on the specified handle.
CTAERR_INVALID_STATE | The line linehd is in uninitialized state.
CTAERR_SVR_COMM | A server communication error occurred.

#### Details

nccQueryCapability queries the capabilities of the protocol on a specified line. Use this function to determine if the current protocol supports a given feature. nccQueryCapability returns an NCC_PROT_CAP structure containing capability information for the protocol.

The NCC_PROT_CAP structure contains the following fields:

Field | Description
--- | ---
size | Number of bytes written at the address pointed to by protcap.
capabilitymask | A bit mask of features implemented by this protocol. See Protocol capabilities for a list of capabilities.