CreateFile() succeeds but the file is not on the disk. - c

Question

HANDLE hFile = CreateFile(LPCTSTR("filename"), // name of the write
GENERIC_READ | GENERIC_WRITE, // open for writing and reading
0, // do not share
NULL, // default security
OPEN_ALWAYS, // create new file only
FILE_ATTRIBUTE_NORMAL, // normal file
NULL);
if(hFile != INVALID_HANDLE_VALUE)
{
printf("Success.\n");
}
CloseHandle(hFile);
The operation succeeds but i can't find 'filename' on the disk.
Does CreateFile() actually creates file on the disk?

Answer 1

I tried a minimal program containing only your code and ... the file was correctly created in current directory ! But only if the program is compiled in ANSI mode, because the LPCTSTR only converts the pointer to be a LPCTSTR but does not convert from ANSI to UNICODE. Only the _T macro does that.
You should use GetCurrentDirectory to control where you try to write the file, and use TCHAR to be UNICODE compatible :
#include <windows.h>
#include <tchar.h>
#include <stdio.h>
int main() {
LPTSTR dir;
DWORD cr = ::GetCurrentDirectory(0, NULL);
cr += 1;
dir = (LPTSTR) malloc(cr * sizeof(TCHAR));
cr = ::GetCurrentDirectory(cr, dir);
/* ::MessageBox(NULL, dir, _T("Current dir"), MB_OK); */
_tprintf(_T("Current dir : %s\n"), dir); // note the _tprintf and _T macro
free(dir);
HANDLE hFile = CreateFile(_T("filename"), // name of the write - _T
GENERIC_READ | GENERIC_WRITE, // open for writing and reading
0, // do not share
NULL, // default security
OPEN_ALWAYS, // create new file only
FILE_ATTRIBUTE_NORMAL, // normal file
NULL);
if(hFile != INVALID_HANDLE_VALUE)
{
printf("Success.\n");
}
CloseHandle(hFile);
return 0;
}
If I compile in UNICODE mode without the _T macro around "filename", the program does create a file, but its name is simply garbage

Answer 2

There is not much information, but here is a blind guess : your file is redirected to the VirtualStore.
Some locations, like "Program Files", are protected on the latest versions of Windows.
If your program is in a protected location and is not run as administrator, the read/write operations will be redirected to C:\Users\MYNAME\AppData\Local\VirtualStore\MYFOLDER.
Running your program as admin should correct this wherever it is located.