getmntent(3) -- Linux man page
NAME
getmntent, setmntent, addmntent, endmntent, hasmntopt,
getmntent_r - get file system descriptor file entry
SYNOPSIS
#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 */
#define _GNU_SOURCE /* or _SVID_SOURCE or _BSD_SOURCE */
#include <mntent.h>
struct mntent *getmntent_r(FILE *fp, struct mntent *mntbuf,
char *buf, int buflen);
DESCRIPTION
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
fp 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> 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 */
};
RETURN VALUE
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.
FILES
/etc/fstab file system description file
/etc/mtab mounted file system description file
CONFORMING TO
The non-reentrant functions are from SunOS 4.1.3.
A routine
getmntent_r()
was introduced in HPUX 10, but it returns an int. The prototype
shown above is glibc-only.
LSB deprecates the functions
endhostent(),
sethostent()
and
setmntent().
NOTES
SysV also has a getmntent() function but the calling sequence
differs, and the returned structure is different. Under SysV
/etc/mnttab
is used.
BSD 4.4 and Digital Unix have a routine getmntinfo(),
a wrapper around the system call getfsstat().
SEE ALSO
fopen(3),
fstab(5)
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