calling system gives exception, waitForProcess

Simon Marlow simonmar at
Mon Dec 5 09:50:37 EST 2005

On 28 November 2005 23:16, Neil Mitchell wrote:

> On Windows XP, with GHC 6.4.1, I get the following error consistently
> when calling "system", from the module System. I get this error on two
> entirely different computers, one slow (750Mhz) system, and one fast
> (3Ghz) system.
> Its easiest to demonstrate when using GHCi, but the problem also
> occurs when running Haskell programs compiled with GHC.
> Prelude System> system "yhi Main"
> PreludeList.!!: on empty list
> *** Exception: waitForProcess: does not exist (No such file or
> directory) 
>> From a windows standard console, in the same current directory, I
>> get: 
> Windows> yhi Main
> PreludeList.!!: on empty list
> When calling yhi using system in other circumstances (on other
> programs), it works fine. The "PreludeList.!! ..." text is being
> generated by the yhi program.
> The yhi program is written in C, and is available from
> Unfortunately this is probably a
> bit too large to use as a minimal test case, and takes quite a while
> to install/configure at the moment.
> Any idea why the waitForProcess error is being raised?

I don't know why this is happening, sorry.  waitForProcess does this:

    if (WaitForSingleObject((HANDLE) handle, INFINITE) == WAIT_OBJECT_0)
	if (GetExitCodeProcess((HANDLE) handle, &retCode) == 0)
	    return -1;
	return retCode;
So it seems that GetExitCodeProcess is returning ENOENT (or the Windows
equivalent) for some reason.  Could something else be calling
GetExitCodeProcess() first?

If you can find a smaller test case, I can probably look into it.


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