Debugging FS-UAE

This page contains some information on how you can better debug FS-UAE problems. In general, checking the contents of FS-UAE.log is a good source of information, as is checking messages printed to stdout. You can make FS-UAE print log output to stdout with:

./fs-uae --stdout

Environment Variables

Some environment variables can be set to aid with debugging problems:


This will cause FS-UAE to log more information about input events to the log file.


This will cause FS-UAE to log all file system operations (for mounted directories) to the log file.




Compiling a Debug Version

If you experience a crash, it is helpful to have a stack trace for when the crash occurs. To compile a version suitable for debugging crashes, you might want to compile a version with debug symbols (-g) and with optimizations tuned for debugging (-Og):

cd fs-uae-(version)
make clean
make make CFLAGS="-g -Og" CXXFLAGS="-g -Og"

You can run FS-UAE from the source directory without installing it, just stay in the top of the project directory and run (using Linux as an example):

./fs-uae <optional args>

You can run FS-UAE through gdb like this:

gdb --args ./fs-uae <other args>

If the program crashes through gdb when input is grabbed, it can be a bit awkward (you may need to switch to a virtual console and kill fs-uae/gdb), so the following is highly recommended:

gdb --args ./fs-uae --no-initial-input-grab <other args>

or, perhaps better: to make FS-UAE never grab input automatically (either on startup or when clicking in the FS-UAE window):

gdb --args ./fs-uae --no-automatic-input-grab <other args>

2 thoughts on “Debugging FS-UAE

  1. Hi ! Is there a special section somewhere for bug reports ? It seems I’m experiencing some strange behaviour with FS-UAE Launcher which, once game and window closed, does not seem to release mouse and keyboard properly.
    FS-UAE 2.1.27dev-0quantal1 / Xubuntu 12.10 x64

    I have already said that, but I must say it again : FS-UAE is totally amazing, a great piece of software ! Good work !

    • Most support / bug reports are done at the English Amiga Board. I have not seen any similar problem, and SDL should automatically release mouse/keyboard on application exit (one would think X would handle this). It could in theory be a Window Manager bug. Another possibility is that FS-UAE does not shutdown cleanly (or crashes). Is there any indication of this? Anything interesting at the end of FS-UAE.log?

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