lineGetIcon - Microsoft Windows Telephony API (TAPI) Programmer's Reference (tapi.hlp)

Microsoft Windows Telephony API
(TAPI) Programmer's Reference

lineGetIcon

The lineGetIcon function allows an application to retrieve a service line device-specific (or provider-specific) icon for display to the user.

LONG lineGetIcon(

DWORD dwDeviceID,
LPCSTR lpszDeviceClass,
LPHICON lphIcon
);

Parameters
dwDeviceID

The line device whose icon is requested.

lpszDeviceClass

A pointer to a NULL-terminated string that identifies a device class name. This device class allows the application to select a specific sub-icon applicable to that device class. This parameter is optional and can be left NULL or empty, in which case the highest-level icon associated with the line device rather than a specified media stream device would be selected.

lphIcon

A pointer to a memory location in which the handle to the icon is returned.

Return Values
Returns zero if the request is successful or a negative error number if an error has occurred. Possible return values are:

LINEERR_BADDEVICEID, LINEERR_OPERATIONFAILED, LINEERR_INVALPOINTER, LINEERR_RESOURCEUNAVAIL, LINEERR_INVALDEVICECLASS, LINEERR_UNINITIALIZED, LINEERR_NOMEM, LINEERR_NODEVICE.

Remarks
The lineGetIcon function causes the provider to return a handle (in lphIcon) to an icon resource (obtained from LoadIcon) that is associated with the specified line. The icon handle is for a resource associated with the provider. The application must use CopyIcon if it wishes to reference the icon after the provider is unloaded, which is unlikely to happen as long as the application has the line open.

The lpszDeviceClass parameter allows the provider to return different icons based on the type of service being referenced by the caller. The permitted strings are the same as for lineGetID. For example, if the line supports the Comm API, passing "COMM" as lpszDeviceClass causes the provider to return an icon related specifically to the Comm device functions of the service provider. The parameters "tapi/line", "", or NULL may be used to request the icon for the line service.

For applications using an API version less than 0x00020000, if the provider does not return an icon (whether because the given device class is invalid or the provider does not support icons), TAPI substitutes a generic Win32 Telephony line device icon. For applications using API version 0x00020000 or greater, TAPI substitutes the default line icon only if the lpszDeviceClass parameter is "tapi/line", "" or NULL. For any other device class, if the given device class is not valid or the provider does not support icons for the class, lineGetIcon returns LINEERR_INVALDEVICECLASS.