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GETMNTENT(3)               Linux Programmer's Manual              GETMNTENT(3)



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 */
       #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

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> 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.

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 HP-UX 10,  but  it
       returns an int.  The prototype shown above is glibc-only.

NOTES
       System  V  also has a getmntent() function but the calling sequence differs, and the returned structure is dif-
       ferent.  Under System V /etc/mnttab is used.  4.4BSD and Digital Unix have a routine  getmntinfo(),  a  wrapper
       around the system call getfsstat().

SEE ALSO
       fopen(3), fstab(5), mount(8)

COLOPHON
       This  page  is part of release 3.22 of the Linux man-pages project.  A description of the project, and informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



                                  2008-06-16                      GETMNTENT(3)