CreateFile works in Debug mode, but not in Release

From:

"Michael Fawcett" <michael.fawcett@gmail.com>

Newsgroups:

microsoft.public.vc.language

Date:

13 Nov 2006 14:50:27 -0800

Message-ID:

<1163458227.538330.315580@f16g2000cwb.googlegroups.com>

I have some code that boils down to CreateFile, CreateFileMapping,
MapViewOfFile. In Debug mode everything works as expected. In Release
mode, CreateFile fails with the message "The process cannot access the
file because it is being used by another process". I have rebooted my
machine and still receive the same error. This happens on the very
first file I attempt to load, so it doesn't appear to be a problem of
loading one incorrectly and then subsequent loads failing. I have also
googled for similar situations to no avail. The relevant code is
posted below. I'm using MSDE 2003 Version 7.1.6030.

boost::shared_ptr<mmap_file> temp(new mmap_file);
temp->file = CreateFile(path.c_str(), GENERIC_READ, 0, 0,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS, 0);
#ifdef _DEBUG
temp->file_size = GetFileSize(temp->file, 0);
if (temp->file != INVALID_HANDLE_VALUE && temp->file_size > 0)
#else
if (temp->file != INVALID_HANDLE_VALUE && GetFileSize(temp->file, 0) >
0)
#endif
{
    temp->mmap = CreateFileMapping(temp->file, 0, PAGE_READONLY |
SEC_COMMIT, 0, 0, 0);
    if (temp->mmap != 0)
    {
        temp->offset = MapViewOfFile(temp->mmap, FILE_MAP_READ, 0, 0, 0);
        if (temp->offset != 0)
        {
            dted_map.insert(std::make_pair(path, temp));
            return temp;
        }
    }
}

The path variable is a std::wstring. For further background, the
mmap_file struct and dted_map instance's type are defined below:

struct mmap_file
{
#ifdef _DEBUG
    size_t file_size;
#endif
    HANDLE file;
    HANDLE mmap;
    const void *offset;

    mmap_file(void) : file(0), mmap(0), offset(0) { }
    ~mmap_file(void)
    {
        try
        {
            if (offset != 0)
                UnmapViewOfFile(offset);

            if (mmap != 0)
                CloseHandle(mmap);

            if (file != 0)
                CloseHandle(file);
        }
        catch (...)
        {
        }
    }
};
typedef stdext::hash_map<std::wstring, boost::shared_ptr<mmap_file> >
map_type;

Thanks for any insight,

Michael Fawcett