Return Codes from the Conversion Routine

When control is returned to your program, register 15 contains one of the following return codes:

Table 1. Actual to Relative Conversion Routine Return Codes
Return Code	Description
0 (X'00')	Successful conversion.
4 (X'04')	CCHH is outside of extent M. Returned relative track number is invalid. If you called the +12 entry point, then it has set the output R byte to X'FE'.
8 (X'08')	Internal access method control blocks are invalid. Call IBM® service if the control blocks should be valid.
12(X'0C')	Internal access method control blocks are invalid. Call IBM service if the control blocks should be valid.
16 (X'10')	Passed extent number M is too big for the data set. If you called the +12 entry point, then it has set the output R byte to X'FE'.
20 (X'14')	The calculated relative track number is too large to be returned. If you called the +0 entry, then the track number exceeds X'FFFF', so the routine returned X'FFFFFE00'. If you called the +12 entry point, then the track number exceeds X'FFFFFF', so the routine returned X'FFFFFFFE'. The likely causes of this are that the DEB is not valid or (for entry +0) the data set is a large format data set, but the track location is more than X'FFFF' tracks into the data set.

Note: For return codes 4, 16 and 20 with the +12 entry point, this routine returns a different value for the R byte (X'FE') than was passed to it.