MDSplus tries to use OFD locks on systems that do not support it

[joshStillerman]

Affiliation MIT PSFC

Version(s) Affected MDSplus version: 7.139.67

Release: alpha_release_7.139.67 Browse: https://github.com/MDSplus/mdsplus/tree/alpha_release_7.139.67 Download: https://github.com/MDSplus/mdsplus/archive/alpha_release_7.139.67.tar.gz

while this version is fine:

MDSplus version: 7.112.1

Release: alpha_release_7.112.1 Browse: https://github.com/MDSplus/mdsplus/tree/alpha_release_7.112.1 Download: https://github.com/MDSplus/mdsplus/archive/alpha_release_7.112.1.tar.gz

Platform RHEL6

Describe the bug I built the current alpha for RHEL6. Things appeared to work. A user reported that there was a complaint about OFD locks when he did a create pulse

[zack-vii]

The corresponding line to decide would be here. https://github.com/MDSplus/mdsplus/blob/a8b4e01560da8a262f9b0bfa8af3b54af959c590/treeshr/RemoteAccess.c#L1563 however, I did not find a reliable way to check if it is supported. It is highly recommended to work on a system with ofd support, as one would have to lock the entire file or implement a handmade locking mechnism that work in between processes. I was fiddling with something like that that would at least allow to safely append. however, it newer worked reliably in all enviroments. As you can see here https://github.com/MDSplus/mdsplus/blob/a8b4e01560da8a262f9b0bfa8af3b54af959c590/treeshr/RemoteAccess.c#L1574 it is just a warning once before turning off the feature.

[joshStillerman]

Thanks! I will test. I reported it when a user complained that his program was / is failing. If worse comes to worse we could add a build switch for it. Though systems that do not support it are really really old. Sadly I have one.