topic Re: Shareable writing into file in Operating System - OpenVMS

Shareable writing into file

AlexanderM — Wed, 02 Oct 2013 06:22:24 GMT

Hello.

I need to write in a log file from several processes.

I am using the next solution:

int logFile;
logFile = open(stampedPath.ptr, O_WRONLY | O_APPEND | O_CREAT, 0666);
write(logFile, buffer.ptr, buffer.len);//to achieve atomic output
close(logFile);

In Linux(Red Hat) it works perfectly.

On OpenVMS I've got the next message in the second process: file currently locked by another user.

I've read about fwrite with additional keys from c language extension, but it is queit hard to find out in google full manual for this keys.

Furthermore:

I am not shure that in this case family of printf functions will give atomic output (in Linux they allow for a processes to mix output).
I dont want to duplicate the code.

Could I resolve this situation with open/write/close using?

Re: Shareable writing into file

AlexanderM — Wed, 02 Oct 2013 06:30:04 GMT

I've got some hurry with it. I've found the post with linked issue.

If the problem and the solution is identical I'll delete this one.

Re: Shareable writing into file

AlexanderM — Wed, 02 Oct 2013 07:52:34 GMT

solution

logFile = open(stampedPath.ptr, O_WRONLY | O_APPEND | O_CREAT, 0666
#ifdef VAX
,"shr = del, get, put, upd", "ctx = stm", "ctx = bin"
#endif