std.process.pipeProcess stalls (linux)

[Carl Sturtivant]

A computationally intensive process run from the command line 
works fine, runs to completion after several minutes, writing a 
few hundred lines of text to standard output and creating, 
writing to and closing around 200 files of size around 20KB.

Now run from std.process.pipeProcess and periodically tested for 
completion with tryWait interleaved with sleep everything seems 
fine for a while. htop reveals that one core is running this at 
100% CPU, and the first 76 files appear one after another, but 
the 77th file is opened and nothing is written to it, and htop 
reveals that the CPU usage has dropped to zero, and yet the 
process is still running according to ps, and this continues 
indefinitely, no error message, no indication from tryWait that 
it is done. htop does not reveal at any point that memory use is 
even half of what is available.

Previously with similar processes that are a somewhat scaled back 
version of the one that fails as above, there's been no 
difference between what happened at the command line and what's 
happening here.

Any ideas or suggestions?