ENUMGEOKEYSCALLBACK

#include "l_bitmap.h"

L_INT pEXT_CALLBACK YourFunction(uTag, uType, uCount, pData, pUserData)

L_UINT16 uTag;

GeoKey ID

L_UINT16 uType;

GeoKey type

L_UINT uCount;

number of GeoKey values

L_VOID* pData;

pointer to GeoKey data

L_VOID* pUserData;

pointer to additional parameters

This function is called for each GeoKey enumerated by the L_EnumFileGeoKeys function.

Parameter Description
uTag GeoKey ID identifying the GeoTIFF key.
uType The type of GeoKey. This indicates whether the data pointed to by pData is SHORT, DOUBLE or ASCII. Possible values are:
  Value Meaning
  TAG_ASCII [2] Byte in the range of 0 to 255. Null-terminated.
  TAG_SHORT [3] Two bytes, unsigned.
  TAG_DOUBLE [12] Eight bytes used as a double-precision floating-point number.
uCount For TAG_ASCII, uCount represents the number of bytes in pData.

For TAG_SHORT and TAG_DOUBLE, uCount represents the number of items in the pData buffer.

Note that for TAG_SHORT and TAG_DOUBLE, uCount does not represent the number of bytes. Instead, it represents the number of items. For example, if uCount is 10 and uType is TAG_DOUBLE, you will need 10 x 8 = 80 bytes to read the tag data.

pData A void pointer that you can use to access a variable or structure containing the GeoKey data. This gives you a way to receive data indirectly from the function that uses this callback function.
pUserData A void pointer that you can use to access a variable or structure containing data that your callback function needs. This gives you a way to receive data indirectly from the function that uses this callback function. (This is the same pointer that you pass in the pUserData parameter of the L_EnumFileGeoKeys function.)

Keep in mind that this is a void pointer, which must be cast to the appropriate data type within your callback function.

Returns

SUCCESS

The function was successful.

< 1

An error occurred. Refer to Return Codes.

Comments

This function will be called for every GeoKey on the page.

Required DLLs and Libraries

LTFIL

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application

See Also

Functions:

L_EnumFileGeoKeys, L_ReadFileGeoKey

Topics:

Implementing TIFF Comments and Tags

 

Raster Image Functions: Working with GeoKeys

Example

For an example, refer to L_EnumFileGeoKeys function.

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