mkdir, mkdirat - create a directory
#include <sys/stat.h>
#include <sys/types.h>
int mkdir(const char *pathname, mode_t mode);
#include <fcntl.h> /* Definition of AT_* constants */
#include <sys/stat.h>
int mkdirat(int dirfd, const char *pathname, mode_t mode);Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
mkdir() attempts to create a directory named pathname.
The argument mode specifies the mode for the new directory (see inode(7)). It is modified by the process's umask in the usual way: in the absence of a default ACL, the mode of the created directory is (mode & ~umask & 0777). Whether other mode bits are honored for the created directory depends on the operating system. For Linux, see NOTES below.
The newly created directory will be owned by the effective user ID of the process. If the directory containing the file has the set-group-ID bit set, or if the filesystem is mounted with BSD group semantics (mount -o bsdgroups or, synonymously mount -o grpid), the new directory will inherit the group ownership from its parent; otherwise it will be owned by the effective group ID of the process.
If the parent directory has the set-group-ID bit set, then so will the newly created directory.
The mkdirat() system call operates in exactly the same way as mkdir(), except for the differences described here.
If the pathname given in pathname is relative, then it is interpreted relative to the directory referred to by the file descriptor dirfd (rather than relative to the current working directory of the calling process, as is done by mkdir() for a relative pathname).
If pathname is relative and dirfd is the special value AT_FDCWD, then pathname is interpreted relative to the current working directory of the calling process (like mkdir()).
If pathname is absolute, then dirfd is ignored.