Use the PUTX macro to update a data set or to write a new output data set using records from an input data set as a base. PUTX updates, replaces, or inserts records from existing data sets, but does not create records.

When you use the PUTX macro to update, each record is returned to the data set referred to by a previous locate mode GET macro. The buffer containing the updated record is flagged and written back to the same location on the direct access storage device where it was read. The block is not written until a GET macro is issued for the next buffer, except when a spanned record is to be updated. In that case, the block is written with the next GET macro.

When you use the PUTX macro to write a new output data set, you can add new records by using the PUT macro. As required, the PUTX macro blocks records, schedules the writing of output buffers, and handles output error correction procedures.