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
);
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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 Professional.
Sample:
None
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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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.