# Vim documentation: debug

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    *debug.txt*     For Vim version 7.0f.  Last change: 2006 Apr 24

    		  VIM REFERENCE MANUAL    by Bram Moolenaar

    Debugging Vim						*debug-vim*

    This is for debugging Vim itself, when it doesn't work properly.
    For debugging Vim scripts, functions, etc. see |debug-scripts|

    1. Location of a crash, using gcc and gdb	|debug-gcc|
    2. Windows Bug Reporting               		|debug-win32|

    ==============================================================================

    1. Location of a crash, using gcc and gdb		*debug-gcc*

    When Vim crashes in one of the test files, and you are using gcc for
    compilation, here is what you can do to find out exactly where Vim crashes.
    This also applies when using the MingW tools.

    1. Compile Vim with the "-g" option (there is a line in the Makefile for this,
       which you can uncomment).

    2. Execute these commands (replace "11" with the test that fails):
    	cd testdir
    	gdb ../vim
    	run -u unix.vim -U NONE -s dotest.in test11.in

    3. Check where Vim crashes, gdb should give a message for this.

    4. Get a stack trace from gdb with this command:
    	where
       You can check out different places in the stack trace with:
    	frame 3
       Replace "3" with one of the numbers in the stack trace.

    ==============================================================================

    2. Windows Bug Reporting                       		*debug-win32*

    If the Windows version of Vim crashes in a reproducible manner, you can take
    some steps to provide a useful bug report.

    GENERIC

    You must obtain the debugger symbols (PDB) file for your executable: gvim.pdb
    for gvim.exe, or vim.pdb for vim.exe. It should be available from the same
    place that you obtained the executable. Be sure to use the PDB that matches
    the EXE (same date).

    If you built the executable yourself with the Microsoft Visual C++ compiler,
    then the PDB was built with the EXE.

    Alternatively, if you have the source files, you can import Make_ivc.mak into
    Visual Studio as a workspace.  Then select a debug configuration, build and
    you can do all kinds of debugging (set breakpoints, watch variables, etc.).

    If you have Visual Studio, use that instead of the VC Toolkit and WinDbg.

    For other compilers, you should always use the corresponding debugger: TD for
    a Vim executable compiled with the Borland compiler; gdb (see above
    |debug-gcc|) for the Cygwin and MinGW compilers.

    Debugging Vim crashes with Visual Studio 2005/Visual C++ 2005 Express

    First launch vim.exe or gvim.exe and then launch Visual Studio.  (If you don't
    have Visual Studio, follow the instructions in src/INSTALLpc.txt to obtain a
    free copy of Visual C++ 2005 Express Edition.)

    On the Tools menu, click Attach to Process.  Choose the Vim process.

    In Vim, reproduce the crash.  A dialog will appear in Visual Studio, telling
    you about the unhandled exception in the Vim process.  Click Break to break
    into the process.

    Visual Studio will pop up another dialog, telling you that no symbols are
    loaded and that the source code cannot be displayed.  Click OK.

    Several windows will open.  Right-click in the Call Stack window.  Choose Load
    Symbols.  The Find Symbols dialog will open, looking for (g)vim.pdb.  Navigate
    to the directory where you have the PDB file and click Open.

    At this point, you should have a full call stack with vim function names and
    line numbers.  Double-click one of the lines and the Find Source dialog will
    appear.  Navigate to the directory where the Vim source is (if you have it.)

    If you don't know how to debug this any further, follow the instructions
    at ":help bug-reports".  Paste the call stack into the bug report.

    If you have a non-free version of Visual Studio, you can save a minidump via
    the Debug menu and send it with the bug report.  A minidump is a small file
    (<100KB), which contains information about the state of your process.

    Debugging Vim with Debugging Tools

    You can download the Microsoft Visual C++ Toolkit from
    	http://msdn.microsoft.com/visualc/vctoolkit2003/
    This contains the command-line tools, but not the Visual Studio IDE.

    The Debugging Tools for Windows can be downloaded from
    	http://www.microsoft.com/whdc/devtools/debugging/default.mspx
    This includes the WinDbg debugger.

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