Data Block Functions (readblock, unreadblock, writeblock)

The readblock function reads a data block (record) from the input file and places it into the argument of a string variable. The unreadblock function resets the input file pointer to the place it was previous to the prior readblock. The writeblock function writes the data contained in the argument of a string variable to the output file.

These functions are commonly used together to pass data blocks in bulk from the input file to the output file. They are useful for maps that are designed to envelope data.

The readblock and writeblock functions are also used in conjunction with the Document Extraction service, to specify the beginning and end of each document in a batch of documents, so that each document can be extracted individually.

For more information about using the corollary Update standard rule to complete the document extraction, see Set an Update Standard Rule as Part of Document Extraction.

These functions enable data to be parsed faster than it would be if each component was translated separately. Parsing with data block function is faster because it avoids parsing fields out of blocks.

For more information about the readblock function, see readblock. For more information about the unreadblock function, see unreadblock. For more information about the writeblock function, see writeblock.

Use this syntax:

readblock(string_variable);
unreadblock();
writeblock(string_variable);