How do I create a directory without using wide strings in C++?

Question

I'm trying to create a directory so that I can put a file into it.

My code:

string Set;
...
CreateDirectory("Game/Sets/" + Set, NULL); // I'm trying to have something like this. CreateDirectory needs wide strings, but Set is narrow.

The variable Set is a narrow string.

I think I might need something other than CreateDirectory, but I don't know what.

You can look here: https://stackoverflow.com/questions/7430248/creating-a-new-directory-in-c — olha, Jun 04 '18 at 17:59
@Olia_Pavliuk I'm assuming they mean wide strings as in ones with 2-4 byte characters (`wchar_t`). This example https://stackoverflow.com/questions/9235679/create-a-directory-if-it-doesnt-exist uses the `WINAPI` to create a directory using `c strings` — Fizz, Jun 04 '18 at 18:01
@drescherjm I don't think so. I don't _need_ `winapi`, but I can use it. — Lego_Master_A, Jun 04 '18 at 18:05
You didn't specify what is wrong with the code as written. Does it fail to compile? Does it fail to create the directory? If so, did you check the result of `CreateDirectory` - does it indicate an error? Do the directories `Game` and `Game/Sets` exist when you execute the code? — user4815162342, Jun 04 '18 at 18:12
Those directories are created initially. I'm trying to create the rest of the directories if they don't exist. — Lego_Master_A, Jun 04 '18 at 18:17

score 3 · Accepted Answer · answered Jun 04 '18 at 18:14

You have to use the string::c_str() member function to get the corresponding const char* (AKA LPCSTR):

string Set;
...
CreateDirectory(("Game/Sets/" + Set).c_str(), NULL);

But it is probably better to use a temporary variable:

string Set;
...
string fullDir = "Game/Sets/" + Set;
CreateDirectory(fullDir.c_str(), NULL);

It can happen that you are compiling a UNICODE program. If that is the case, you will get an error because const char* is not convertible to const wchar_t*. The solution is to call the ANSI version of the function:

CreateDirectoryA(fullDir.c_str(), NULL);

If you prefer you can use the ANSI function even if there is no error, just to be extra consistent.

Remember that CreateDirectory is actually a macro that expands to CreateDirectoryW or CreateDirectoryA depending on the project configuration. You can use any one of these three names as you see fit.

Thank you **SO** much! I was trying to get this straight for a long time! :D — Lego_Master_A, Jun 04 '18 at 18:26

How do I create a directory without using wide strings in C++?

1 Answers1