5.7. Closing a Stream As already mentioned, REXX does not have an explicit way of opening a stream. Nor does it have an explicit way of closing a stream. There is one semi-standard method: If you call LINEOUT(), but omit both the data to be written and the new current write position, then the implementation is defined to set the current write position to the end-of-file. Furthermore, it is allowed by TRL to do something “magic” in addition. It is not explicitly defined what this magic is, but TRL suggests that it may be closing the stream, flushing the stream, or committing changes done previously to the stream. In SAA, the definition is strengthened to state that the “magic” is closing, provided that the environment supports that operation. A similar operating can be performed by calling CHAROUT() with neither data nor a new position. However, in this case, both TRL and SAA leave it totally up to the implementation whether or not the file is to be closed. One can wonder whether the changes for LINEOUT() in SAA with respect to TRL should also have been done to CHAROUT(), but that this was forgotten. TRL2 does not indicate that LINEIN() or CHARIN() can be used to close a string. Thus, the closest one gets to a standard way of closing input files is to call e.g. LINEOUT(); although it is conceptually suspect to call an output routine for an input file. The historical reasons for this omission are perhaps that flushing output files is vital , while the concept of flushing is irrelevant for input files; flushing is an important part of closing a file, and that explains why closing is only indicated for output files. Thus, the statement: call lineout ‘myfile.txt’ might be used to close the stream myfile.txt in some implementations. However, it is not guaranteed to close the stream, so you cannot depend on this for scripts of maximum portability, but it’s better than nothing. However, note that if it closes the stream, then also the current read position is affected. If it merely flushes the stream, then only the current write position is likely to be affected.