A/UX: Increasing Maximum Open Files per Process

Article Change History
----------------------
08/31/92 - REVIEWED
o For technical accuracy.

Is there a way to increase the maximum number of files that one A/UX
process can open simultaneously?

Normally the maximum is 32 (and this includes stdin, stdout, and stderr).
In stdio.h we found the identifier FOPEN_MAX, but modifying this isn't
sufficient. We also found the identifiers OPEN_MAX in limits.h and NOFILE
in sys/params.h. However, modifying these identifiers to a higher value
(for example 40) in our own source doesn't work either.

Is it possible that these values are fixed in certain system libraries or
in the object code of the system calls (open, creat)? Is there an
easy way to change this, both in A/UX 2.0.1 and 3.0?

There is no way to adjust the number of open files available to each
process without recompiling the kernel, because it was hard-coded in the
kernel. If you try to use "adb" to change this value, other kernel
structures will be affected and mixed. You won't be able to recompile the
kernel without kernel sources.

The upcoming A/UX 3.0 release increases the maximum number of open files
per process to 128. These defined constants, OPEN_MAX (in
/usr/include/limits.h) and NOFILE (in /usr/include/sys/param.h), are in
A/UX 3.0