GETMNTENT(3)

NAME
       getmntent,  setmntent, addmntent, endmntent, hasmntopt, getmntent_r - get file system descriptor file
       entry

SYNOPSIS
       #include 
       #include 

       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 

       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 .

       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 sub-
       string that matches opt.  See  and  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  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  rep-
       resent  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 fail-
       ure.

       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.  LSB  deprecates  the  functions
       endhostent(), sethostent() and setmntent().

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  getm-
       ntinfo(), a wrapper around the system call getfsstat().

SEE ALSO
       , ,