-bool path_is_absolute(const char *p);
-char *path_make_absolute(const char *p, const char *prefix);
-char *path_make_absolute_cwd(const char *p);
-char *path_kill_slashes(char *path);
-char *path_startswith(const char *path, const char *prefix);
-bool path_equal(const char *a, const char *b);
+bool path_is_absolute(const char *p) _pure_;
+char* path_make_absolute(const char *p, const char *prefix);
+char* path_make_absolute_cwd(const char *p);
+char* path_kill_slashes(char *path);
+char* path_startswith(const char *path, const char *prefix) _pure_;
+bool path_equal(const char *a, const char *b) _pure_;