Re: OpenVMS getdtablesize.c

[John E. Malmberg]

On 6/28/2017 3:56 PM, Bruno Haible wrote:

John E. Malmberg wrote:

OpenVMS has the function.  Configure detects it exists, but the test for
it working is failing.
...
The OpenVMS getdtablesize() is returning the maximum number of open
files that a process can have.

It is not returning the highest file descriptor + 1 that can be used in
the system.  That number is 65535 for OpenVMS Alpha and Integrity.

That is why it is failing the configure test.

There are two possibilities:
   (a) change the configure test so that is duplicates
       fd 0 to 1, 2, 3, ..., getdtablesize() and see if that fails.
   (b) special-case OpenVMS.

I'm not in favour of (a) because it might allocate so many file descriptors
that the kernel gets problems.

So (b). Just add a few lines

   case "$host_os" in
     vms*) ...

at the appropriate place. Can you propose such a patch?


Please try to approximate the wording of POSIX [1] as closely as possible.

Bruno

[1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/getrlimit.html

According to that link, a system is not required to fail a request for a file descriptor to be created higher than RLIMIT_NOFILE.

Attached is a patch for the test to pass on OpenVMS.

Regards,
-John

0001-getdtablesize.m4-Fix-for-OpenVMS.patch.gz
Description: GNU Zip compressed data