如何列出目录而不包括包含dirent.h的文件？

Question

I have searched this a lot about this thing: How to make C print all directories without dirent.h. I found something called tiny dirent or something but it wasn't so useful for me becasue it had a licence on it. I have found seveal things more that wasn't uselful. Now, I want to do it myself that I found out the only way is to write one by myself. I am using GCC to compile and I use linux to make one. So, how can I make my own dirent.h without including any header files?

Answer 1

This is operating system specific, since not all C implementations (think of some C program for Arduino ) have directories.

How can I list directories without including files including dirent.h?

By using some other libraries, or directly some syscalls(2) .

Did you consider using ntfw(3) , or readdir(3) ?

So, how can I make my own dirent.h without including any header files?

You create C source files with a good editor such as GNU emacs . Or you use (or write) a program generating some C code (eg GNU bison ).

You should read a good operating system textbook if you want to create your own OS. Then see also OSDEV , and budget several years of full time work. See also LinuxFromScratch , and study for inspiration the source code of the Linux kernel or of FreeBSD .

I am using GCC to compile

Be sure to read the documentation of GCC ( user and internals ). Use it as gcc -Wall -Wextra -g . You might code your GCC plugin , or generate some C code with eg GPP

Answer 2

On eg Linux the struct dirent structure returned by readdir have a d_type member which you can check for the type DT_DIR .

---

If you're writing your own POSIX-like operating system you can decide yourself what members the dirent structure contains, like the above mentioned d_type member.

You won't be having opendir / readdir / closedir in your kernel, but have to implement such functionality yourself.