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This IOCTL can be implemented by GPS hardware manufacturers to return data used by the GPS hardware to more quickly obtain a GPS fix. For example, GPS hardware in a mobile phone may have the ability to more quickly obtain a GPS fix using information about the current mobile phone tower(s) used by a mobile phone. Applications can read this data from the GPS hardware using this IOCTL.

An application using the GPS Intermediate Driver can save the data retrieved by calling this IOCTL, say, on shutdown, and then provide the results to the GPS hardware, at startup, by calling IOCTL_GPS_WRITE_ASSISTED. This data may provide enough information to the GPS hardware to enable the hardware to obtain a GPS fix more quickly than it would without additional data.

For more information about how to use and implement this IOCTL, see Implementing GPS Intermediate Driver Hardware IOCTLs.

Note   Almanac data that can be used to enable faster GPS fixes should be retrieved using IOCTL_GPS_READ_ALMANAC.


Applications using the GPS Intermediate Driver should pass a pointer that can hold data using the lpOutBuffer parameter of the DeviceIOControl function.

GPS hardware manufacturers that implement this IOCTL should use the lpOutBuffer pointer to return data currently used by the GPS hardware.

It is important to note that this data is only meaningful to the GPS hardware. The data is completely opaque to an application using the GPS Intermediate Driver. The degree to which applications can interact with this information is limited to saving the results of IOCTL_GPS_READ_ASSISTED and then providing the saved results to the GPS hardware using IOCTL_GPS_WRITE_ASSISTED.

Return Values

GPS hardware manufacturers may return TRUE if the hardware device driver was able to provide this data, and FALSE otherwise. However, this is not required and applications should not rely on the return value obtained when using this IOCTL.


OS Versions: Windows CE 5.01 and later.
Header: GPSDev.h.

See Also

GPS Intermediate Driver IOCTLs | Implementing GPS Intermediate Driver Hardware IOCTLs | DeviceIOControl | IOCTL_GPS_READ_ALMANAC | IOCTL_GPS_WRITE_ASSISTED

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