mount(S)                       6 January 1993                       mount(S)


 Name

    mount - mount a filesystem

 Syntax


    cc ... -lc


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

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


 Description

    mount requests that a removable filesystem 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.  fstyp is the filesystem type
    number.  The sysfs(S) system call can be used to determine the filesystem
    type number.  Note that if both the MSDATA and MSFSS flag bits of mflag
    are off, the filesystem type defaults to the root filesystem type.  Only
    if either flag is on is fstyp used to indicate the filesystem type.

    If the MSDATA flag is set in mflag, the system expects the dataptr and
    datalen arguments to be present.  Together they describe a block of
    file-system specific data at address dataptr of length datalen.  This is
    interpreted by file-system specific code within the operating system and
    its format depends upon the filesystem type.  A particular filesystem
    type may not require this data, in which case dataptr and datalen should
    both be zero.  Note that MSFSS is obsolete and is ignored if MSDATA is
    also set, but if MSFSS is set and MSDATA is not, dataptr and datalen
    are both assumed to be zero.

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

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

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

    mount fails if one or more of the following is true:

    [EBUSY]        1. dir is currently mounted on, is someone's current work-
                   ing directory, or is otherwise busy.
                   2. The device associated with spec is currently mounted.
                   3. There are no more mount table entries.

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

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

    [EMULTIHOP]    Components of path require hopping to multiple remote ma-
                   chines.

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

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

    [ENOSPC]       The filesystem state in the super block is not FsOKAY and
                   mflag requests write permission.

    [ENOTBLK]      spec is not a block special device.

    [ENOTDIR]      1. A component of a path prefix is not a directory.
                   2. dir is not a directory.

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

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

    [EREMOTE]      spec is remote and cannot be mounted.

    [EROFS]        spec is write-protected and mflag requests write permis-
                   sion.


 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.

 See also

    filesystem(FP), fsname(ADM), labelit(ADM), mount(ADM), sysfs(S),
    umount(S)

 Standards conformance

    mount is conformant with:
    AT&T SVID Issue 2, but has been withdrawn from XPG3.