HP 3000 Manuals

Accessing Files Programmer's Guide

Summary of Overrides 

If a FILE command has been entered that contradicts some of the
HPFOPEN/FOPEN parameters for a file, which takes precedence?  What
happens if some parameters are left out?  The file system maintains a
hierarchy of overrides for just such situations (illustrated in Figure
2-1 ): 


          Figure 2-1.  File System Hierarchy of Overrides 

Since the physical characteristics of a file cannot be changed after it
has been created, it makes sense that the file label would take
precedence over all commands.  Other determinants are effective only when
a new file is being created.


NOTE  FILE commands and HPFOPEN/FOPEN calls cannot alter physical
      characteristics of an existing file.

MPE/iX 5.0 Documentation