ImageGear for C and C++ on Windows v19.0
IG_ISIS_tag_get_rational_default
| API Reference Guide > ISIS Component API Reference > ISIS Component Functions Reference > Tag Functions > IG_ISIS_tag_get_rational_default |
Get default value of a tag of type rational.
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AT_ERRCOUNT ACCUAPI IG_ISIS_tag_get_rational_default(
HISISDRV hDriver,
AT_MODE nTag,
WORD wIndex,
LPAT_ISIS_RAT lpValue
);
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| Name | Type | Description |
|---|---|---|
| hDriver | HISISDRV | The handle to the driver. |
| nTag | AT_MODE | Specifies the type rational tag for which to return the default value. |
| wIndex | WORD | Specifies the index of the element to get. Most tags have only one element, in which case wIndex must be zero. Use IG_ISIS_tag_get_length_default to determine how many elements a tag contains. |
| lpValue | LPAT_ISIS_RAT | Points to the default value of the tag after this function completes. |
Returns the number of ImageGear errors that occurred during this function call. If there are no errors, the return value is IGE_SUCCESS.
This function does not process image pixels.
The IG_ISIS_tag_get_rational_default function retrieves the rational value that is the default value of the specified tag.
Use IG_ISIS_tag_get_rational_default to retrieve the default value of the type rational tag specified in nTag. Use IG_ISIS_tag_get_length_default to get the number of elements in the tag. If the tag has only one element, wIndex must be zero. If the tag has multiple elements, loop on IG_ISIS_tag_get_rational_default to obtain all elements of the default value of the tag.
Use of IG_ISIS_tag_get_rational_default on a tag other than one of type rational is undefined. At best, this will cause an invalid return value or a operating system error message, and at worst will cause the system to crash.
IG_ISIS_tag_get_length, IG_ISIS_tag_get_rational, IG_ISIS_tag_set_rational.