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 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  struc-
       ture  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  char-
       acters  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  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 3.25 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)