use stat in c to check if file or directory code example
Example: c check dir/file
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
int is_regular_file(const char *path)
{
struct stat path_stat;
stat(path, &path_stat);
return S_ISREG(path_stat.st_mode);
}