PA_GetBlobField

version 2003

PA_GetBlobField (tNum; fNum; blob) → long

Parameter	Type		Description
tNum	short	→	Table number of the field to access
fNum	short	→	Field number of the field to access
blob	void*	←	Pointer to the BLOB data
Function result	long	←	BLOB size in bytes

Description

The routine PA_GetBlobField puts the content of the BLOB field number fNum of the current record of the table number tNum , in the data pointed to by blob , and returns its size in bytes.

If the field is not a BLOB field, the routine leaves blob unchanged, returns 0 and an error code in PA_GetLastError .

If BLOB size is unknown, call the function a first time with blob equal to zero. The returned value will be the size of the needed buffer. Allocate the buffer and call the function again with the correct buffer.


   
    blob

is a copy of the original, you can manipulate it and dispose of it. If the BLOB is large, you can get the


   eER_NotEnoughMemory

error. You can get a handle to the BLOB simply by calling


   PA_GetBlobHandleField.

Example

Getting a BLOB field content:

   char   *theBlob;
   long   blobSize;
 
   // First call the routine with a null pointer to get the BLOB size
      blobSize = PA_GetBlobField( tNum, fNum, 0 );
   // Then allocate the buffer
      theBlob = malloc( blobSize );
   // If it is ok, get the BLOB
      if( theBlob )
      {
         blobSize = PA_GetBlobField( tNum, fNum, theBlob );
      // Work with it
         /* . . . */
      // Cleanup
         free( theBlob );
      }

Error Handling

Use PA_GetLastError to see if an error occurred ( eER_InvalidFileNumber , eER_InvalidFieldNumber , etc.)