Using Physical Files Instead of Source Physical Files

When a source physical file is used for stream I⁄O, the first 12 bytes of each record are not visible to your application. They are used to store the record number and update time. These 12 bytes are an extra load that the ILE C stream I/O functions must manipulate. For example:

• When performing output, these 12 bytes must be initialized to zero.
• When performing input, these 12 bytes must be fetched even though they are not passed to your application.

Because the ILE C stream I⁄O functions dynamically create a source physical file when opening a text file that does not already exist for output, create the file as a physical file before you start your application.