Gnuplot.Gnuplot() will fail to start a gnuplot process anytime
the current working directory (CWD) is a UNC path (e.g.
\host\foo\bar) rather than a DOS path (e.g. V:\foo\bar). The
underlying cause is a "feature" of cmd.exe documented at
The symptom of this is that when you try to execute gnuplot
commands, you get a traceback like this when the write() on the
pipe to the child process fails:
Traceback (most recent call last):
File "testprog.py", line 34, in ?
File "Gnuplot_Gnuplot.pyc", line 199, in call
File "Gnuplot\gp_win32.pyc", line 125, in call
IOError: [Errno 22] Invalid argument
The fix is to use subprocess.Popen() with shell=False. The
subprocess module has it's own set of bugs under Win32 that you
have to work around:
I'm currently testing a fix.