1 Bugs in MPSIDL itself

No entries to speak of as yet... I'm sure some will appear fairly soon. Please send contributions (ie. bugs) to

2 Bugs in interactions between MPSIDL and other software

2.1 Don't use -O2 on HPUX


  • HPUX with gcc 2.95.2

If you're trying to use MPSIDL on HPUX (version 10.20 - I don't know if this bug affects other versions) with gcc 2.95.2, then don't use -O2 on your compiler command-line. It causes breakage. The problem is that if you use:

  • -O2
  • exceptions
  • method-pointers

in the same program (like the MPSIDL InetTransport subsystem does), G++ will generate very incorrect code which will cause the exception to be thrown multiple times and caught in extremely wrong places.

Your code will NOT work properly when exceptions are thrown if you're linking against MPSIDL and using -O2, or if any of your code meets the three criteria listed above all at the same time.

I've filed a bug against gcc; it'll be interesting to see what comes of it. The problem report identifier is "c++/2135". You can read the bug report and related correspondence at

An example of the bug in action is in [:hpuxoptimiserbug:] (a C++ source file), if you're interested in investigating the problem further.

2.2 Windows 95 doesn't work properly

While Windows Me works fine with MPSIDL, I haven't yet managed to get Windows 95 to work anywhere near as well. MPSIDL builds successfully, of course, but when I run it, WSAStartup returns WSAVERNOTSUPPORTED. This happens when I request either version "0" or version "1"... and the very same code works fine on Windows Me!

Any ideas? Send 'em to the MailingLists!

3 Problems building MPSIDL

3.1 The Java doesn't compile!

Are you using a Java 1.1 implementation? If so: mps.jar should build correctly, but any of the Java programs in the "tools" subdirectory which use Swing components will probably fail to build, unless you have somehow managed to put Swing into your default Java 1.1 CLASSPATH.

If, on the other hand, you're using a 1.2 or 1.3 implementation, then you've found a bug. If you can fix it, please send me a description of the problem and the solution you came up with; otherwise, please let me know about the problem either by posting a bug on Sourceforge, or by emailing me directly. Thanks!


  • Compile mps.jar by hand, and ignore the existence of the Swing-based tools (cd libmps/java; make; make install) - this should always work
  • or: upgrade to Java 1.2 or Java 1.3 in order to get Swing Java tools working
  • or: somehow get a swing.jar which works with JDK 1.1 into your default CLASSPATH

3.2 I can't use GCC 3.0.x or GCC 3.1!

Support for the stricter (more correct) C++ rules laid down by GCC versions 3.x was added between versions 0.1.4 and 0.1.5. If you want to use MPS with GCC version 3.x, you will need to get a recent CVS checkout, since version 0.1.5 has not yet been released.

Note that ref.h also changed as part of implementing GCC 3.x compatibility - you will need to download a new copy (see DownloadMpsIdl).

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(last modified 05 July 2002 by surazal) Logo