MOUNT(2)                             SysV                             MOUNT(2)



NAME
     mount - mount a file system

SYNOPSIS
     int mount (spec, dir, mflag, fstyp)
     char *spec, *dir;
     int mflag, fstyp;

DESCRIPTION
     mount requests that a removable file system contained on the block
     special file identified by spec be mounted on the directory identified by
     dir.  spec and dir are pointers to path names.  mflag is optional.  fstyp
     is not used (see "Notes").

     Upon successful completion, references to the file dir will refer to the
     root directory on the mounted file system.

     The low-order bit of mflag is used to control write permission on the
     mounted file system; if 1, writing is forbidden, otherwise writing is
     permitted according to individual file accessibility.

     mount may be invoked only by the super-user.  It is intended for use only
     by the mount(1M) utility.

     mount will fail if one or more of the following are true:

     [EPERM]       The effective user ID is not super-user.

     [ENOENT]      Any of the named files does not exist.

     [ENOTDIR]     A component of a path prefix is not a directory.

     [EREMOTE]     spec is remote and cannot be mounted.

     [ENOTBLK]     spec is not a block special device.

     [ENXIO]       The device associated with spec does not exist.

     [ENOTDIR]     dir is not a directory.

     [EFAULT]      spec or dir points outside the allocated address space of
                   the process.

     [EBUSY]       dir already is serving as a mount point, is someone's
                   current working directory, or is otherwise busy.

     [EBUSY]       The device associated with spec is currently mounted.

     [EBUSY]       There are no more mount table entries.

     [EROFS]       spec is write protected and mflag requests write
                   permission.

     [ENOSPC]      The file system state in the super-block is not fsOKAY and
                   mflag requests write permission.

     [EINVAL]      The super block has an invalid magic number or the fstyp is
                   invalid or mflag is not valid.

SEE ALSO
     sysfs(2), umount(2), fs(4).

     mount(1M) in Managing SysV System Software.

DIAGNOSTICS
     Upon successful completion a value of 0 is returned.  Otherwise, a value
     of -1 is returned and errno is set to indicate the error.

NOTES
     Under other implementations, mount fails if any of the following are
     true:

     [ENOLINK]     path points to a remote machine and the link to that
                   machine is no longer active.

     [EMULTIHOP]   Components of path require hopping to multiple remote
                   machines.

     In some other implementations, fstyp is the file system type number.
     These implementations also may provide values for mflag in the file
     <sys/mount.h>.  In this case, if the MS_FSS flag bit of mflag is off, the
     file system type will default to the root file system type. Only if the
     bit is on will fstyp be used to indicate the file system type.