[Roxxor91]

I'd like to output a scalar value (say for example runTime.value()) to a ASCII text file in real time during a simulation.
My current implementation is:

in main solver:

fileName outputFile(runTime.path()/"log.custom");
OFstream customLog(outputFile);
dimensionedScalar t("t", dimTime, runTime.value());

at every "outputTime":

customLog << "Time: " << t.value() << endl;

Doing so, the "log.custom" file gets filled with lines of "Time: 0.xxx" and this is fine. However, if I terminate my solver (with CTRL+C, or the "kill" command), or if I monitor the log file (using "tail -f log.custom"), I always see the log file empty UNTIL the end of the simulation.

On the other hand, if I redirect the standard output to a logfile (i.e. mySolverFoam > log.mySolverFoam), I am able to monitor in real time the output.

Any idea how to get my second log to behave like the standard one?

[dlahaye]

I wonder whether you need to use something equivalent to flush, see https://cplusplus.com/reference/ostream/flush-free/

[Roxxor91]

Originally Posted by dlahaye

I wonder whether you need to use something equivalent to flush, see https://cplusplus.com/reference/ostream/flush-free/

Thanks for your suggestion, it works!
I am surprised flush is not implemented in "OFStream"...


Update: After checking the source of OFstream, there is indeed a flush function that can be called as

 Info << "test" << nl << flush;

Moreover, the newline and flush methods are combined in "endl" as

 Info << "test" << endl;

After making sure I used "endl", the flushing does happen, and I get what I wanted. So to the ones reading this, it is possible to stick to OpenFOAM's OFstream objects, and the use of "endl" combines a newline with a flush.