The PHONEBUTTONINFO structure contains information about a button on a phone device.
typedef struct phonebuttoninfo_tag {
DWORD dwTotalSize;
DWORD dwNeededSize;
DWORD dwUsedSize;
DWORD dwButtonMode;
DWORD dwButtonFunction;
DWORD dwButtonTextSize;
DWORD dwButtonTextOffset;
DWORD dwDevSpecificSize;
DWORD dwDevSpecificOffset;
DWORD dwButtonState;
} PHONEBUTTONINFO, FAR *LPPHONEBUTTONINFO;
Device-specific extensions should use the DevSpecific (dwDevSpecificSize and dwDevSpecificOffset) variably sized area of this data structure.
Older applications are compiled without this field in the PHONEBUTTONINFO structure, and using a SIZEOF PHONEBUTTONINFO smaller than the new size. The application passes in a dwAPIVersion parameter with the phoneOpen function, which can be used for guidance by TAPI in handling this situation. If the application passes in a dwTotalSize less than the size of the fixed portion of the structure as defined in the specified dwAPIVersion, PHONEERR_STRUCTURETOOSMALL is returned. If sufficient memory has been allocated by the application, before calling TSPI_phoneGetButtonInfo, TAPI sets the dwNeededSize and dwUsedSize members to the fixed size of the structure as it existed in the specified API version.
New service providers (which support the new API version) must examine the API version passed in. If the API version is less than the highest version supported by the provider, the service provider must not fill in fields not supported in older API versions, as these would fall in the variable portion of the older structure.
New applications must be cognizant of the API version negotiated, and not examine the contents of fields in the fixed portion beyond the original end of the fixed portion of the structure for the negotiated API version.
Version: Use TAPI version 1.4 and later.
Header: Declared in tapi.h.