std::filesystem::path:: make_preferred

Windows can use / as a separator, but prefers \ , so make_preferred converts the forward slashes to backslashes. On the other hand, POSIX does not use \ as a separator, because backslashes are valid filename characters — the Windows path on POSIX actually refers to a file with the name "a \\ b \\ c" . For this reason the "separators" are not converted.

#include <filesystem>
#include <iostream>
 
int main()
{
    std::filesystem::path
        windows_path("a\\b\\c"),
        posix_path("a/b/c");
 
    std::cout
        << "Windows path: "
        << windows_path << " -> "
        << windows_path.make_preferred() << '\n'
        << "POSIX path: "
        << posix_path << " -> "
        << posix_path.make_preferred() << '\n';
}

Output:

// on Windows
Windows path: "a\\b\\c" -> "a\\b\\c"
POSIX path: "a/b/c" -> "a\\b\\c"
 
// on POSIX
Windows path: "a\\b\\c" -> "a\\b\\c"
POSIX path: "a/b/c" -> "a/b/c"