MOUNT(2)            Linux Programmer's Manual            MOUNT(2)

NAME
       mount, umount - mount and unmount filesystems.

SYNOPSIS
       #include <sys/mount.h>
       #include <linux/fs.h>        /* very unwise */

       int  mount(const  char  *specialfile,  const  char * dir ,
       const char * filesystemtype, unsigned long rwflag ,  const
       void * data);

       int umount(const char *specialfile);

       int umount(const char *dir);

DESCRIPTION
       mount  attaches  the  filesystem  specified by specialfile
       (which is often a device name) to the directory  specified
       by dir.

       umount  removes the attachment of the filesystem specified
       by specialfile or dir.

       Only the super-user may mount and unmount filesystems.

       The filesystemtype argument may take  one  of  the  values
       listed   in   /proc/filesystems   (like  "minix",  "ext2",
       "msdos", "proc", "nfs", "iso9660" etc.).

       The rwflag argument has the magic number 0xC0ED in the top
       16   bits,   and   various  mount  flags  (as  defined  in
       <linux/fs.h>) in the low order 16 bits:
       #define MS_RDONLY    1 /* mount read-only */
       #define MS_NOSUID    2 /* ignore suid and sgid bits */
       #define MS_NODEV     4 /* disallow access to device special files */
       #define MS_NOEXEC    8 /* disallow program execution */
       #define MS_SYNC     16 /* writes are synced at once */
       #define MS_REMOUNT  32 /* alter flags of a mounted FS */
       #define MS_MGC_VAL 0xC0ED0000
       If the magic number is absent, then the last two arguments
       are not used.

       The  data  argument  is  interpreted by the different file
       systems.

RETURN VALUE
       On success, zero is returned.  On error, -1  is  returned,
       and errno is set appropriately.

ERRORS
       The  error  values given below result from filesystem type
       independent errors. Each filesystem type may have its  own
       special errors and its own special behavior.  See the ker-
       nel source code for details.

       EPERM   The user is not the super-user.

       ENODEV  Filesystemtype not configured in the kernel.

       ENOTBLK Specialfile is not a block device (if a device was
               required).

       EBUSY   Specialfile  is  already mounted. Or, it cannot be
               remounted read-only, because it still holds  files
               open for writing.  Or, it cannot be mounted on dir
               because dir is  still  busy  (it  is  the  working
               directory of some task, the mount point of another
               device, has open files, etc.).

       EINVAL  Specialfile had  an  invalid  superblock.   Or,  a
               remount  was  attempted, while specialfile was not
               already  mounted  on  dir.   Or,  an  umount   was
               attempted, while dir was not a mount point.

       EFAULT  One  of  the  pointer arguments points outside the
               user address space.

       ENOMEM  The kernel could not allocate a free page to  copy
               filenames or data into.

       ENAMETOOLONG
               A pathname was longer than MAXPATHLEN.

       ENOENT  A  pathname  was empty or had a nonexistent compo-
               nent.

       ENOTDIR The second argument, or  a  prefix  of  the  first
               argument, is not a directory.

       EACCES  A component of a path was not searchable.
               Or,  mounting a read-only filesystem was attempted
               without giving the MS_RDONLY flag.
               Or, the block device Specialfile is located  on  a
               filesystem mounted with the MS_NODEV option.

       ENXIO   The  major  number of the block device specialfile
               is out of range.

       EMFILE  (In case no block device is  required:)  Table  of
               dummy devices is full.

CONFORMING TO
       These  functions are Linux-specific and should not be used
       in programs intended to be portable.

SEE ALSO
       mount(8), umount(8)

Linux 1.1.67               28 Nov 1994                          1