Digital

NAME

mount − mount a file system using the SVID-2 function

SYNOPSIS

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

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

PARAMETERS

specPoints to a path name that is a removable file system contained on the block special file. 

dirPoints to a path name that is the directory on which spec is mounted. 

mflagSpecifies whether additional file system data is included.  The valid flag is MS_DATA. 

fstypSpecifies the file system type number. 

dataptrPoints to the address of a block of file system specific data. 

datalenSpecifies the length of the file system specific data. 

DESCRIPTION

The mount() function mounts a removable file system contained on the block special file identified by spec.  The dir argument identifies the mount point. 

When the MS_DATA flag bit of mflag is off, the file system type defaults to the root file system type.  Only when the MS_DATA flag bit is on, should you use the fstyp argument to indicate the file system type.  Also, the dataptr and datalen arguments, which describe a block of file system specific data, must be present when the MS_DATA flag is set.  The file system specific code within the operating system interprets the data.  The data’s format depends on the file system type.  If a file system type does not require this data, dataptr and datalen should both be zero. 

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

After a successful mount(), references to the dir file refer to the mounted file system’s root directory. 

Only super-user can invoke the mount function.  Its intended purpose is to be used by the mount(8) utility. 

NOTES

Two mount() functions are supported by OSF/1: the BSD mount() and the SVID-2 mount().  The BSD function is the default mount() and it is documented in mount(2).  To use the SVID-2 version of mount(), which is documented on this reference page, you must link with the libsys5 library before you link with libc. 

RETURN VALUES

The mount function returns 0 when the file system is successfully mounted.  Otherwise, −1 is returned and errno is set to indicate the error. 

If the mount functions fails, errno is set to one of the following values:

[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]The file system identified by spec is remote and cannot be mounted. 

[ENOLINK]The path argument 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. 

[ENOTBLK]The spec argument is not a block special device. 

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

[ENOTDIR]The dir argument is not a directory. 

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

[EBUSY]The dir argument is a user’s current working directory, is mounted on a user’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]The 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. 

RELATED INFORMATION

Command: mount(8). 

Function: statfs(2). 

System V Compatibility User’s Guide