Why would fopen fail to open a file that exists?
- by void
I'm on Windows XP using Visual Studio 6 (yes I know it's old) building/maintaining a C++ DLL. I'm encountered a problem with fopen failing to open an existing file, it always returns NULL.
I've tried:
Checking errno and _doserrno by setting both to zero and then checking them again, both remain zero, and thus GetLastError() reports no errors. I know fopen isn't required to set errno when it encounters an error according to a C standard.
Hardcoding the file path, which are not relative.
Tried on another developers machine which the same result.
The really strange thing is CreateFile works and the file can be read with ReadFile. We believe this works in a release build, however we are also seeing some very odd behaviour in other areas of the application and we're not sure if this is related.
The code is below, I don't see anything odd it looks quite standard to me. The source file hasn't changed for just under half a year.
HRESULT CDataHandler::LoadFile( CStdString szFilePath )
{
//Code
FILE* pFile;
if ( NULL == ( pFile = fopen( szFilePath.c_str(), "rb") ) )
{
return S_FALSE;
}
//More code
}
