NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | FILES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON
GETMNTENT(3) Linux Programmer's Manual GETMNTENT(3)
getmntent, setmntent, addmntent, endmntent, hasmntopt, getmntent_r - get file
system descriptor file entry
#include <stdio.h>
#include <mntent.h>
FILE *setmntent(const char *filename, const char *type);
struct mntent *getmntent(FILE *fp);
int addmntent(FILE *fp, const struct mntent *mnt);
int endmntent(FILE *fp);
char *hasmntopt(const struct mntent *mnt, const char *opt);
/* GNU extension */
#include <mntent.h>
struct mntent *getmntent_r(FILE *fp, struct mntent *mntbuf,
char *buf, int buflen);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
getmntent_r(): _BSD_SOURCE || _SVID_SOURCE
These routines are used to access the file system description file /etc/fstab
and the mounted file system description file /etc/mtab.
The setmntent() function opens the file system description file filename and
returns a file pointer which can be used by getmntent(). The argument type is
the type of access required and can take the same values as the mode argument
of fopen(3).
The getmntent() function reads the next line from the file system description
file fp and returns a pointer to a structure containing the broken out fields
from a line in the file. The pointer points to a static area of memory which
is overwritten by subsequent calls to getmntent().
The addmntent() function adds the mntent structure mnt to the end of the open
file fp.
The endmntent() function closes the file system description file fp.
The hasmntopt() function scans the mnt_opts field (see below) of the mntent
structure mnt for a substring that matches opt. See <mntent.h> and mount(8)
for valid mount options.
The reentrant getmntent_r() function is similar to getmntent(), but stores the
struct mount in the provided *mntbuf and stores the strings pointed to by the
entries in that struct in the provided array buf of size buflen.
The mntent structure is defined in <mntent.h> as follows:
struct mntent {
char *mnt_fsname; /* name of mounted file system */
char *mnt_dir; /* file system path prefix */
char *mnt_type; /* mount type (see mntent.h) */
char *mnt_opts; /* mount options (see mntent.h) */
int mnt_freq; /* dump frequency in days */
int mnt_passno; /* pass number on parallel fsck */
};
Since fields in the mtab and fstab files are separated by whitespace, octal
escapes are used to represent the four characters space (\040), tab (\011),
newline (\012) and backslash (\134) in those files when they occur in one of
the four strings in a mntent structure. The routines addmntent() and
getmntent() will convert from string representation to escaped representation
and back.
The getmntent() and getmntent_r() functions return a pointer to the mntent
structure or NULL on failure.
The addmntent() function returns 0 on success and 1 on failure.
The endmntent() function always returns 1.
The hasmntopt() function returns the address of the substring if a match is
found and NULL otherwise.
/etc/fstab file system description file
/etc/mtab mounted file system description file
The non-reentrant functions are from SunOS 4.1.3. A routine getmntent_r() was
introduced in HP-UX 10, but it returns an int. The prototype shown above is
glibc-only.
System V also has a getmntent() function but the calling sequence differs, and
the returned structure is different. Under System V /etc/mnttab is used.
4.4BSD and Digital Unix have a routine getmntinfo(), a wrapper around the
system call getfsstat().
fopen(3), fstab(5), mount(8)
This page is part of release 3.23 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
2009-09-15 GETMNTENT(3)