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This function returns an opaque data structure object, the contents of which are specific to the line (service provider) and device class. The data structure object stores the current configuration of a media-stream device associated with the line device.
Syntax
LONG WINAPI lineGetDevConfig( DWORD dwDeviceID, LPVARSTRING lpDeviceConfig, LPCSTR lpszDeviceClass ); |
Parameters
- dwDeviceID
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Line device to be configured.
- lpDeviceConfig
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Pointer to the memory location of type VARSTRINGwhere the device configuration structure is returned. Upon successful completion of the request, this location is filled with the device configuration. The dwStringFormatmember in the VARSTRINGstructure is set to STRINGFORMAT_BINARY. Prior to calling lineGetDevConfig, the application should set the dwTotalSizemember of this structure to indicate the amount of memory available to TAPI for returning information.
- lpszDeviceClass
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Pointer to a null-terminated string that specifies the device class of the device whose configuration is requested. Valid device class lineGetIDstrings are the same as those specified for the function.
Return Value
Returns zero if the function succeeds or a negative error number if an error occurs. The following table shows the return values for this function.
Value | Description |
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LINEERR_BADDEVICEID |
The device identifier is incorrect. |
LINEERR_NODRIVER |
The driver was not found. |
LINEERR_INVALDEVICECLASS |
The device class is invalid. |
LINEERR_OPERATIONUNAVAIL |
The operation is unavailable. |
LINEERR_INVALPOINTER |
The pointer is invalid. |
LINEERR_RESOURCEUNAVAIL |
The resources are unavailable. |
LINEERR_STRUCTURETOOSMALL |
The structure is too small. |
LINEERR_OPERATIONFAILED |
The operation failed. |
LINEERR_NOMEM |
Not enough memory is available. |
LINEERR_UNINITIALIZED |
A parameter is uninitialized. |
LINEERR_NODEVICE |
The device was not found. |
Remarks
The lineGetDevConfigfunction can be used to retrieve a data structure from TAPI that specifies the configuration of a media stream device associated with a particular line device. For example, the contents of this structure could specify data rate, character format, modulation schemes, and error control protocol settings for a datamodem media device associated with the line.
Typically, an application calls lineGetIDto identify the media stream device associated with a line, and then calls the lineConfigDialogfunction to allow the user to set up the device configuration. It could then call lineGetDevConfig, and save the configuration information in a phone book (or other database) associated with a particular call destination. When the user later wishes to call the same destination again, the lineSetDevConfigfunction can be used to restore the configuration settings selected by the user. The functions lineSetDevConfig, lineConfigDialog, and lineGetDevConfigcan be used, in that order, to allow the user to view and update the settings.
The exact format of the data contained within the structure is specific to the line and media stream API (device class), is undocumented, and is undefined. The structure returned by this function cannot be directly accessed or manipulated by the application, but can only be stored intact and later used in lineSetDevConfigto restore the settings. The structure also cannot necessarily be passed to other devices, even of the same device class (although this can work in some instances, it is not guaranteed).
In Windows Embedded CE, the lineGetDevConfigfunction for a unimodem line device returns the default DevConfig. This saves memory space. If the DevConfig in use is the same as the default, it does not need to be stored.
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This function is for TAPI version 2.0 and later. |
Requirements
Header | tapi.h |
Library | coredll.lib |
Windows Embedded CE | Windows CE 1.0 and later |
Windows Mobile | Windows Mobile Version 5.0 and later |