Question

(追加100分！)谁能帮我找到linux/unix系统下创建文件夹的C语言源码？

用C语言，不能调用其它的程序（如md.exe），或者给我md.exe的C语言源码也行…我就想弄明白文件夹是怎么回事…
一楼的
#include "libbb.h"
似乎找不到……

Answer 1

去下载busybox的源码,在busybox-XXXX/coreutils/mkdir.c

/* vi: set sw=4 ts=4: */
/*
* Mini mkdir implementation for busybox
*
* Copyright (C) 2001 Matt Kraai <kraai@alumni.carnegiemellon.edu>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/

/* BB_AUDIT SUSv3 compliant */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/mkdir.html */

/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
*
* Fixed broken permission setting when -p was used; especially in
* conjunction with -m.
*/

/* Nov 28, 2006 Yoshinori Sato <ysato@users.sourceforge.jp>: Add SELinux Support.
*/

#include "libbb.h"

/* This is a NOFORK applet. Be very careful! */

#if ENABLE_FEATURE_MKDIR_LONG_OPTIONS
static const char mkdir_longopts[] ALIGN1 =
"mode\0" Required_argument "m"
"parents\0" No_argument "p"
#if ENABLE_SELINUX
"context\0" Required_argument "Z"
#endif
;
#endif

int mkdir_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int mkdir_main(int argc, char **argv)
{
mode_t mode = (mode_t)(-1);
int status = EXIT_SUCCESS;
int flags = 0;
unsigned opt;
char *smode;
#if ENABLE_SELINUX
security_context_t scontext;
#endif

#if ENABLE_FEATURE_MKDIR_LONG_OPTIONS
applet_long_options = mkdir_longopts;
#endif
opt = getopt32(argv, "m:p" USE_SELINUX("Z:"), &smode USE_SELINUX(,&scontext));
if (opt & 1) {
mode = 0777;
if (!bb_parse_mode(smode, &mode)) {
bb_error_msg_and_die("invalid mode '%s'", smode);
}
}
if (opt & 2)
flags |= FILEUTILS_RECUR;
#if ENABLE_SELINUX
if (opt & 4) {
selinux_or_die();
setfscreatecon_or_die(scontext);
}
#endif

if (optind == argc) {
bb_show_usage();
}

argv += optind;

do {
if (bb_make_directory(*argv, mode, flags)) {
status = EXIT_FAILURE;
}
} while (*++argv);

return status;
}

Answer 2

#include <sys/stat.h>
#include <sys/types.h>
int mkdir(const char *pathname, mode_t mode);

文件夹（目录文件），也是一个文件，只不过它的内空是指向inode数据块的索引而已。还有，要用unix的思想方式思考这个问题。unix下一切皆文件，光盘，硬盘，串口，网卡，声卡，文件夹，都可以当作文件来对待，文件的性质就在于可以读，写，执行。