Question

I want to check if file returned by readdir is directory.
I tried do it using DT_DIR constant (as man readdir says) but it’s undefined. What file should I include to get it?

Now I use

#include <sys/types.h>
#include <dirent.h>
#include <stdlib.h>
#include <errno.h>

gcc version is 4.6.1

Compilation string:

gcc a.c --std=c99 -Wall

Answer 1

You need to have the _BSD_SOURCE feature test macro defined to get those defines, they are not standard, and GCC does not define that macro when compiling for C99.

gcc -std=c99 -D_BSD_SOURCE -Wall a.c