NAME

       mkdir - make a directory

SYNOPSIS

       #include <sys/stat.h>

       int mkdir(const char *path, mode_t mode);

DESCRIPTION

       The mkdir() function shall create a new directory with name path. The file permission bits
       of the new directory shall be initialized from mode. These file  permission  bits  of  the
       mode argument shall be modified by the process' file creation mask.

       When  bits  in  mode  other  than  the  file permission bits are set, the meaning of these
       additional bits is implementation-defined.

       The directory's user ID shall be set to the process' effective user  ID.  The  directory's
       group ID shall be set to the group ID of the parent directory or to the effective group ID
       of the process.  Implementations shall provide a way to initialize the  directory's  group
       ID  to the group ID of the parent directory. Implementations may, but need not, provide an
       implementation-defined way to initialize the directory's group ID to the  effective  group
       ID of the calling process.

       The newly created directory shall be an empty directory.

       If path names a symbolic link, mkdir() shall fail and set errno to [EEXIST].

       Upon  successful  completion,  mkdir()  shall  mark for update the st_atime, st_ctime, and
       st_mtime fields of the directory. Also, the st_ctime and st_mtime fields of the  directory
       that contains the new entry shall be marked for update.

RETURN VALUE

       Upon  successful  completion,  mkdir() shall return 0. Otherwise, -1 shall be returned, no
       directory shall be created, and errno shall be set to indicate the error.

ERRORS

       The mkdir() function shall fail if:

       EACCES Search permission is denied on a component of the path prefix, or write  permission
              is denied on the parent directory of the directory to be created.

       EEXIST The named file exists.

       ELOOP  A loop exists in symbolic links encountered during resolution of the path argument.

       EMLINK The link count of the parent directory would exceed {LINK_MAX}.

       ENAMETOOLONG
              The  length  of  the  path  argument  exceeds {PATH_MAX} or a pathname component is
              longer than {NAME_MAX}.

       ENOENT A component of the path  prefix  specified  by  path  does  not  name  an  existing
              directory or path is an empty string.

       ENOSPC The  file  system  does  not  contain  enough space to hold the contents of the new
              directory or to extend the parent directory of the new directory.

       ENOTDIR
              A component of the path prefix is not a directory.

       EROFS  The parent directory resides on a read-only file system.

       The mkdir() function may fail if:

       ELOOP  More than {SYMLOOP_MAX} symbolic links were encountered during  resolution  of  the
              path argument.

       ENAMETOOLONG
              As a result of encountering a symbolic link in resolution of the path argument, the
              length of the substituted pathname string exceeded {PATH_MAX}.

       The following sections are informative.

EXAMPLES

   Creating a Directory
       The following  example  shows  how  to  create  a  directory  named  /home/cnd/mod1,  with
       read/write/search  permissions  for  owner and group, and with read/search permissions for
       others.

              #include <sys/types.h>
              #include <sys/stat.h>

              int status;
              ...
              status = mkdir("/home/cnd/mod1", S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);

APPLICATION USAGE

       None.

RATIONALE

       The mkdir() function originated in 4.2 BSD and was added to System V in Release 3.0.

       4.3 BSD detects [ENAMETOOLONG].

       The POSIX.1-1990 standard required that the group ID of a newly created directory  be  set
       to  the  group  ID  of  its  parent directory or to the effective group ID of the creating
       process. FIPS 151-2 required that implementations provide a way to have the  group  ID  be
       set to the group ID of the containing directory, but did not prohibit implementations also
       supporting a way to set the group ID to the effective group ID of  the  creating  process.
       Conforming  applications  should not assume which group ID will be used. If it matters, an
       application can use chown() to set the  group  ID  after  the  directory  is  created,  or
       determine under what conditions the implementation will set the desired group ID.

FUTURE DIRECTIONS

       None.

SEE ALSO

       umask() , the Base Definitions volume of IEEE Std 1003.1-2001, <sys/stat.h>, <sys/types.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2003 Edition, Standard for Information Technology  --  Portable  Operating  System
       Interface  (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
       the Institute of Electrical and Electronics Engineers, Inc and  The  Open  Group.  In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .