IG_ISIS_choice_get

Get the total number of legal values for a tag.

Declaration:

	Copy Code
AT_ERRCOUNT ACCUAPI IG_ISIS_choice_get_count( HISISDRV hDriver, AT_MODE nTag, LPWORD lpwCount );

Arguments:

Name	Type	Description
hDriver	HISISDRV	The handle to the driver.
nTag	AT_MODE	Specifies the tag for which the count of legal choice values is being requested.
lpwCount	LPWORD	The address of an unsigned integer in which the number of legal values will be stored. If a choice node is defined for the tag, then this parameter will contain the available number of values in the currently-selected node. If no choice node is defined for the tag, this parameter returns a value of 1.

Return Value:

Returns the number of ImageGear errors that occurred during this function call. If there are no errors, the return value is IGE_SUCCESS.

Supported Raster Image Formats:

This function does not process image pixels.

Example:

See IG_ISIS_choice_get_ascii example.

Remarks:

The IG_ISIS_choice_get_count function retrieves the total number of legal values from a specified tag.

The IG_ISIS_choice_get_countfunction can be used to determine the valid range of the wIndex parameter to use in other IG_ISIS_choice_get... functions. The range is zero to (*lpwCount - 1).

If the tag is defined, IG_ISIS_choice_get_count always returns IGE_SUCCESS. The value returned in lpwCount is valid, and its value depends on the type of choice node for the specified tag:

If a choice node is defined for the tag, lpwCount specifies the available number of values in the current node.
If the choice node is a range node, the value returned in lpwCount specifies the number of values computed by ((MAX - MIN) / STEP).
If no choice node is defined for the tag, lpwCount contains the value 1.

IG_ISIS_choice_get_count returns the correct value even if the choices for a tag are represented as a range (low, high, step).