Try giving an absolute path to 'mkdir'. I'm fairly sure that the exec*
family does not use the PATH environment.

I tried the different versions and used execvp precisely because it's supposed to provide the path. But I admit I never tried giving it an entire path.

BCS:

That's what the 'p' in 'vp' stand for: path.

OTOH I don't remember if the exec's tack on the exe name to the args so you might need to do:

execvp("mkdir",["mkdir","test"]);

Because arg #0 is the name of the exec itself?

***

Ok, I tried your suggestions and obtained some results. Right now, I can even make dmd compile some simple file, like this:

execvp("dmd", ["dmd", "test.d"];

It doesn't do anything with just

execvp("dmd", ["test.d"]);

Now, my goal is to activate the dot executable from graphviz
( http://www.graphviz.org )

and... it works if I use

execvp("dot", ["dot", /* arg lis */]);
thank to you both!

strangely, it takes 22s to produce the pdf, as opposed to about 3s at the command line...
I think initially, I stopped it before it could finish its work.

Philippe