Hi,
         I only just joined this list so please excuse aberrant behaviour.

         I am also in the same situation as Matt, but I have more 
information about it.

         First, you can easily work around it by telling devstudio to 
invoke flex through bash:

                 c:\cygwin\bin\bash -c "flex ..."

         This is with 2.5.31-1, my previous version was 2.5.4-2.

         Previous experience with DevStudio has suggested to me that it 
invokes external commands via command.com, so I checked invoking flex 
manually with identical arguments under bash and under command.com.  The 
result is that it always seems to work under bash, but under command.com it 
can give a command-line summary, but not compile my script (I only have the 
one script handy to test it under).  So I think the problem is invocation 
under command.com, not anything about DevStudio per se.

         I'm attaching a cygcheck output.

         I'm not sure whether flex should invoke under command.com?  e.g. 
is there a difference between invoking an isolated cygwin executable by its 
full path, and invoking one which tries to access other executables, and 
which may not have a PATH set up?

         In any case, I have a simple work-around, so this is JFYI.

         Ian Badcoe



>I want to use flex in Visual Studio, but it won't run. It just says:
>
>flex: fatal internal error, exec failed
>
>
>It worked before I upgraded Cygwin a few days ago.  I don't know what
>version of flex I was using before, but this happens with version 2.5.31.
>
>Thanks!
>Matt Gregory