Glorious Bugs

I still remember that bug! Because it grabbed my two days and delayed the delivery. Well, the story goes like this – It was during late summer of 2004. I was working in a DVD writer project. Internally we were using a third party DVD writer library named BHA Gold. Well, my project was a wrapper library for the BHA Gold library.

Well, the bug was this – There is a config file in my project, which exist in the same folder, together with exe. Before writing DVD, I’ve to read some settings from the config file. But the bug is this. During startup, I could open the file. But if I write one DVD using BHA gold, then when i tried to open the same file once again, it shows error!

At last its been found that the culprit is the api – _chdir(). The DVD writing library was calling this api internally to prepare the directory tree, and once this api is called, the default directory will be changed to the specified directory and during next time, while opening the setting file, it shows an error that “file not found”! Since the setting file does not exist in the new default directory.

Well, in such cases you could use the api – SetCurrentDirectory(). See the code snippet to set the current directory as exe’s folder path.

#include "Shlwapi.h"
...
// Get the full path of current exe file.
TCHAR FilePath[MAX_PATH] = { 0 };
GetModuleFileName( 0, FilePath, MAX_PATH );

// Strip the exe filename from path and get folder name.
PathRemoveFileSpec( FilePath );    

// Set the current working directory.
SetCurrentDirectory( FilePath );

Don’t forget to add Shlwapi.lib to project settings.

Targeted Audience – Advanced.