PHONEBUTTONINFO structure (tapi.h)
The PHONEBUTTONINFO structure contains information about a button on a phone device. This structure is used by multiple TAPI and TSPI functions.
Syntax
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, *LPPHONEBUTTONINFO;
Members
dwTotalSize
Total size allocated to this data structure, in bytes.
dwNeededSize
Size for this data structure that is needed to hold all the returned information, in bytes.
dwUsedSize
Size of the portion of this data structure that contains useful information, in bytes.
dwButtonMode
Mode or general usage class of the button. This member uses one of the PHONEBUTTONMODE_ Constants.
dwButtonFunction
Function assigned to the button. This member uses one of the PHONEBUTTONFUNCTION_ Constants.
dwButtonTextSize
Size of the descriptive text for the button, in bytes.
dwButtonTextOffset
Offset from the beginning of this structure to the variably sized field containing descriptive text for this button. The format of this information is as specified in the dwStringFormat member of the phone's device capabilities. The size of the field is specified by dwButtonTextSize.
dwDevSpecificSize
Size of the device-specific field, in bytes. If the device-specific field is a pointer to a string, the size must include the null terminator.
dwDevSpecificOffset
Offset from the beginning of the structure to the variably sized device-specific field. The size of the field is specified by dwDevSpecificSize.
dwButtonState
For the phoneGetButtonInfo function, this field indicates the current state of the button, using the PHONEBUTTONSTATE_ Constants. This field is ignored by the phoneSetButtonInfo function.
Remarks
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 the TSPI_phoneGetButtonInfo function, 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.
Requirements
| Requirement | Value |
|---|---|
| Header | tapi.h |