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 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 getm-
       ntent().

       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 (40),
       tab  (11), newline (12) and backslash (134) in those files when they occur in one of the four strings in a mntent structure.  The rou-
       tines 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 3.27 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)