question about clock()

[timfield]

If I have a program with threads running in parallel and I use clock()
to time segments of code, will that time include processor time of all
threads in the process, or just the calling thread?

 

[Keith Thompson]

If I have a program with threads running in parallel and I use clock()
to time segments of code, will that time include processor time of all
threads in the process, or just the calling thread?

I don't know. Standard C doesn't support threads, so the standard's
description of clock() doesn't distinguish between threads, processes,
etc.

Check your system's documentation, or try a newsgroup for your system.

 

[Jordan Abel]

If I have a program with threads running in parallel and I use clock()
to time segments of code, will that time include processor time of all
threads in the process, or just the calling thread?

It appears to do it across the whole process on my system, but threads
aren't in standard C, so who knows.

 

[Michael]

Hi, just tested it and it seems to time all the threads on the process.

 

[Keith Thompson]

Hi, just tested it and it seems to time all the threads on the process.

You just tested what? Read <http://cfaj.freeshell.org/google/>.

This means that it applies to all the threads in the process *on your
system*. That may or may not be of any use to anyone else.

Standard C doesn't support threads, so there's no meaningful way to
answer the original question in the context of this newsgroup. Some
particular systems or secondary standards might provide a meaningful
answer (for example, I suspect the POSIX standard specifies this), but
that's a question for a different newsgroup, perhaps
comp.programming.threads or comp.unix.programmer.