ART_global_block

This function queries a global named block for its data returning it in lpBlockData.

Declaration:

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AT_ERRCOUNT ART_global_block_query( HIGEAR hIGear, const LPART_BLOCK_NAME lpBlockName, LPVOID lpBlockData, LPDWORD lpBlockSize );

Arguments:

Name	Type	Description
hIGear	HIGEAR	HIGEAR handle to the image.
lpBlockName	const LPART_BLOCK_NAME	A far pointer to an 8 byte array of memory that specifies the type of block to query. The block type is either an ART-defined constant beginning with ART_BLOCK or a user-defined block. See ARTAPI.H file for the full list of ART-defined constants.
lpBlockData	LPVOID	A far VOID pointer which returns block data.
lpBlockSize	LPDWORD	The size of lpBlockData (in bytes).

Return Value:

Returns the number of ImageGear errors that occurred during the function call.

Supported Raster Image Formats:

All pixel formats supported by ImageGear for C and C++.

Example:

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HIGEAR hIGear; /* HIGEAR handle of image / LPVOID blockData; / data in global block / DWORD blockSize; / size of block, in bytes / AT_ERRCOUNT nErrCount; / number of errors on the / / error stack / / get the block size / nErrCount = ART_global_block_query(hIGear, ART_BLOCK_GROUP, NULL, &blockSize); blockData = (LPVOID)alloca(blockSize); / but the data into blockData */ nErrCount = ART_global_block_query(hIGear, ART_BLOCK_GROUP, blockData, &blockSize);

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HIGEAR hIGear; /* HIGEAR handle of image */
LPVOID blockData; /* data in global block  */
DWORD blockSize; /* size of block, in bytes */
AT_ERRCOUNT nErrCount; /* number of errors on the */
/* error stack  */
/* get the block size */
nErrCount = ART_global_block_query(hIGear, 
ART_BLOCK_GROUP, NULL, &blockSize);
blockData = (LPVOID)alloca(blockSize);
/* but the data into blockData */
nErrCount = ART_global_block_query(hIGear, 
ART_BLOCK_GROUP, blockData, &blockSize);

Remarks:

The buffer pointed to by lpBlockData must be large enough to fit the named block data. The size of the block is returned by lpBlockSize.

To find the size of a buffer necessary to hold the block data, call ART_global_block_query() with lpBlockData set to NULL. lpBlockSize returns the size of the block.

An error is set if any of the following conditions are met:

hIGear does not reference a valid ImageGear handle.
lpBlockName does not point to a valid address.
lpBlockData does not point to a valid address or is not NULL.
lpBlockData points to a buffer smaller than the block data.
lpBlockSize points to an invalid address.
lpBlockSize points to a value smaller than the size of the block data.