Get the length of an ASCII value from a driver.
Declaration:
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AT_ERRCOUNT ACCUAPI IG_ISIS_choice_get_ascii_len(
HISISDRV hDriver,
AT_MODE nTag,
WORD wIndex,
LPWORD lpwLength
);
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Arguments:
| Name | Type | Description |
| hDriver | HISISDRV | The handle to the driver. |
| nTag | AT_MODE | The tag for which the length of an ASCII value is being requested. |
| wIndex | WORD | An index to a particular element of the array of tag values. |
| lpwLength | LPWORD | The address of an unsigned integer in which the string length will be stored. |
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.