ILE C/C++ Programmer's Guide


I/O Feedback Area

The I/O feedback area is a part of the open data path for the file that is updated after each successful non-blocked I/O operation. If record blocking is taking place, the I/O feedback is updated after each block of records is transferred between your program and the Data Management system.

The I/O feedback consists of two parts: one part that is common to all file types, and one part that is specific to the type of file.

To assign a pointer to the common part of the I/O feedback area, use the _Riofbk() function. To assign a pointer to the part of the I/O feedback area that is specific to the type of file, add the offset contained in the file_dep_fb_offset field of the common part to a pointer to the common part.

Note:
The offset is in bytes, so you need to cast the pointer (char *) to the common part to a pointer to character when performing the pointer arithmetic. The structures that map to the I/O feedback areas are the structures contained in the <xxfdbk.h> header file.


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