NAME

       getmntent, setmntent, addmntent, endmntent, hasmntopt, getmntent_r - get filesystem 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 filesystem description file /etc/fstab and the mounted filesystem
       description file /etc/mtab.

       The setmntent() function opens the filesystem 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  filesystem  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 filesystem 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 filesystem */
               char *mnt_dir;      /* filesystem 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          filesystem description file
       /etc/mtab           mounted filesystem description file

CONFORMING TO

       The nonreentrant 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
       different.  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 3.54 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)