Question

I am reading the content of the current library with readdir, but I would like to treat only files and not directories. How do I know that I am pointing to a directory and not to a file?

Answer 1

You can use lstat, and the S_ISDIR macro.

E.g. without error-checking:

struct stat buffer;
int status;
char path[PATH_MAX];
DIR *dir = opendir(dir_name);
... 
struct dirent *de = readdir(dir);
sprintf(path, "%s/%s", dir_name, de->d_name);
status = lstat(path, &buffer);
if(S_ISDIR(buffer.st_mode))
{
   ...
}

EDIT: Fixed to include directory in lstat path (per el.pescado). As noted by R Samuel Klatchko, you may want to take a whitelist approach (S_ISREG) instead of blacklisting types as they come up.