Get the length of an ASCII value from a driver.

Declaration:

AT_ERRCOUNT ACCUAPI IG_ISIS_choice_get_ascii_len(
        HISISDRV hDriver,
        AT_MODE nTag,
        WORD wIndex,
        LPWORD lpwLength
);

Arguments:

Return Value:

Error count.

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_ascii_len function fills in lpwLength with the length of the string referenced by wIndex from tag nTag.

This function is often used in conjunction with IG_ISIS_choice_get_ascii to determine the required size of that function's lpszValue parameter.

This function must be used only for tags which have a type of IG_ISIS_TAG_TYPE_STRING. Use the IG_ISIS_tag_get_type function to determine the type of a tag.

wIndex must reference the actual number of legal values defined for a given tag. The IG_ISIS_choice_get_count function can be used to determine the total number of legal values for a tag. wIndex must be at least 0 and at most the value returned by IG_ISIS_choice_get_count - 1. The constants IG_ISIS_CHOICE_LOW, IG_ISIS_CHOICE_HIGH, and IG_ISIS_CHOICE_STEP are not valid values for wIndex.

Note that IG_ISIS_choice_get_ascii_len may return a different value for each member of an array of valid values referenced by wIndex.

See Also:

IG_ISIS_choice_get_ascii

IG_ISIS_choice_get_count

IG_ISIS_tag_get_type