CODEWITHSUNDEEP
cwindows
user3140972
user3140972

Reputation: 1065

What is the appropriate way of getting file attributes in C on Windows?

I would like to get file attributes in C on cross platform. I tried stat and access, they both work fine on Unix-like systems (Ubuntu, Mac OS X). But this commands misbehave on Windows, for example: whether there is read permission for file or not, stat and access both always return true.

Here is my function, which works correctly on Unix-like systems.

int is_readable(char *file)
{
    struct stat fileStat;
    stat(file, &fileStat);
    return (fileStat.st_mode & S_IRUSR);
}

What is the right way of getting file attributes in C on Windows (cross platform solution would be even better)?

Upvotes: 0

Views: 896

Answers (2)

flotto
flotto

Reputation: 561

File permissions on unix like systems and windows are completely different. So I think, the easiest is simply try reading the file and deal with the errno/return code.

Upvotes: 2

unwind
unwind

Reputation: 399833

On Win32, access() really should work. I suspect you used it wrong, it returns 0 on success. The documentation is pretty clear:

Each function returns 0 if the file has the given mode. The function returns –1 if the named file does not exist or does not have the given mode; [...]

It's easy to incorrectly interpret -1 as true; you must compare against 0.

Also, I would argue that your function doesn't work correctly, it doesn't handle the case when stat() fails. I/O is brittle, you must error-check!

Upvotes: 1

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