Write to File in nonexistent path

Hi,
I just found that if I use fstream to write to a file under nonexistent directory, it will not report any error or do any thing you want during execution. For example, where there is no directory called "tmp" under current directory,

Code:

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#include <fstream>

using namespace std;

int main()
{
    ofstream fout( "./tmp/results.txt", ios::app );
    fout << 2 <<endl;
    return 0;
}

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How to specify in code to create a directory if it is not existent ? Thanks!

Quote:

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Originally Posted by lehe

How to specify in code to create a directory if it is not existent ? Thanks!

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Forget creating the directory, how do you determine if you need to create it? The answer is, it's not portable. The closest thing to a portable method is stat(), and that's only UNIX-portable.

Thanks!
So testing if a directory exists is also system-dependent? In Linux, how to make fstream to report if the directory it tries to write in does not exist, and to make one?