@node setmntent, unix
@findex setmntent
@subheading Syntax

@example
#include <mntent.h>

FILE *setmntent(char *filename, const char *mode);
@end example

@subheading Description

This function returns an open @code{FILE*} pointer which can be used by
@code{getmntent} (@pxref{getmntent}).  The arguments @var{filename} and
@var{mode} are always ignored under MS-DOS, but for portability should
be set, accordingly, to the name of the file which describes the mounted
filesystems and the open mode of that file (like the @var{mode} argument
to @code{fopen}, @pxref{fopen}).  (There is no single standard for the
name of the file that keeps the mounted filesystems, but it is usually,
although not always, listed in the header @code{<mntent.h>}.)

@subheading Return Value

The @code{FILE*} pointer is returned.  For MS-DOS, this @code{FILE*} is
not a real pointer and may only be used by @code{getmntent}.

@subheading Portability

@portability !ansi, !posix

@subheading Example

@example
#include <mntent.h>
#if defined(MNT_MNTTAB)
#define MNTTAB_FILE MNT_MNTTAB
#elif defined(MNTTABNAME)
#define MNTTAB_FILE MNTTABNAME
#else
#define MNTTAB_FILE "/etc/mnttab"
#endif

  FILE *mnt_fp = setmntent (MNTTAB_FILE, "r");
@end example

@c ----------------------------------------------------------------------
@node getmntent, unix
@findex getmntent
@tindex mntent@r{ structure}
@subheading Syntax

@example
#include <mntent.h>

struct mntent *getmntent(FILE *filep);
@end example

@subheading Description

This function returns information about the various drives that are
available to your program.  Beginning with drive @file{A:}, information
is retrieved for successive drives with successive calls to
@code{getmntent}.  Note that drives @file{A:} and @file{B:} will only be
returned if there is an MS-DOS formatted disk in the drive; empty drives
are skipped.  For systems with a single floppy drive, it is returned as
if it were mounted on @file{A:/} or @file{B:/}, depending on how it was
last referenced (and if there is a disk in the drive).

The argument @var{filep} should be a @code{FILE*} pointer returned by
@code{setmntent} (@pxref{setmntent}).

For each drive scanned, a pointer to a static structure of the following
type is returned:

@example
struct mntent
@{
    char * mnt_fsname;  /* The name of this file system */
    char * mnt_dir;     /* The root directory of this file system */
    char * mnt_type;	/* Filesystem type */
    char * mnt_opts;    /* Options, see below */
    int    mnt_freq;    /* -1 */
    int    mnt_passno;  /* -1 */
    long   mnt_time;    /* -1 */
@};
@end example

DJGPP implementation returns the following in the first 4 fields of
@code{struct mntent}:

@table @code

@item mnt_fsname

For networked and CD-ROM drives, this is the name of root directory in
the form @file{\\HOST\PATH} (this is called a @dfn{UNC name}).

For drives compressed with DoubleSpace, @code{mnt_fsname} is the string
@file{@var{X}:\DBLSPACE.@var{NNN}}, where @var{X} is the drive letter of
the host drive and @var{NNN} is the sequence number of the Compressed
Volume File.

For drives compressed with Stacker, @code{mnt_fsname} is the string
@file{@var{X}:\STACVOL.@var{NNN}}, where @var{X} and @var{NNN} are as
for DoubleSpace drives.

For drives compressed with Jam (a shareware disk compression software),
@code{mnt_fsname} is the full name of the Jam archive file.

For SUBSTed drives, @code{mnt_fsname} is the actual directory name that
that was SUBSTed to emulate a drive.

JOINed drives get their @code{mnt_fsname} as if they were NOT JOINed
(i.e., either the label name or the default @samp{Drive @var{X}:}).

For drives with a volume label, @code{mnt_fsname} is the name of the
label; otherwise the string @samp{Drive @var{X}:}, where @var{X} is the
drive letter.

@item mnt_dir

For most drives, this is the name of its root directory @file{@var{X}:/}
(where @var{X} is the drive letter), except that JOINed drives get
@code{mnt_dir} as the name of the directory to which they were JOINed.

For systems with a single floppy drive (which can be referenced as either
@file{a:/} or @file{b:/}), the mount directory will be returned as one
of these, depending on which drive letter was last used to reference
that drive.

@item mnt_type

@example
 "fd"     for floppy disks
 "hd"     for hard disks
 "dblsp"  for disks compressed with DoubleSpace
 "stac"   for disks compressed with Stacker
 "jam"    for disks compressed with Jam
 "cdrom"  for CD-ROM drives
 "ram"    for RAM disks
 "subst"  for SUBSTed directories
 "join"   for JOINed disks
 "net"    for networked drives
@end example

@item mnt_opts

The string @samp{ro,dev=@var{XX}} for CD-ROM drives,
@samp{rw,dev=@var{XX}} for all the others, where @var{XX} is the
hexadecimal drive number of the REAL drive on which this filesystem
resides.  That is, if you call @code{stat} on @var{mnt_fsname}, you will
get the numeric equivalent of @var{XX} in @code{st_dev} member of
@code{struct stat}.  E.g., for drive @file{C:} you will get
@samp{rw,dev=02}.  Note that SUBSTed and JOINed drives get the drive
numbers as if SUBST and JOIN were @strong{not} in effect.

@end table

@subheading Return Value

This function returns a pointer to a @code{struct mntent}, or
@code{NULL} if there are no more drives to report on.

@subheading Portability

@portability !ansi, !posix

@subheading Example

@example
struct mntent *m;
FILE *f;
f = setmntent("/etc/mnttab", "r");
while ((m = getmntent(f)))
  printf("Drive %s, name %s\n", m->mnt_dir, m->mnt_fsname);
endmntent(f);
@end example

@c ----------------------------------------------------------------------
@node addmntent, unix
@findex addmntent
@subheading Syntax

@example
#include <mntent.h>

int addmntent(FILE *filep, const struct mntent *mnt);
@end example

@subheading Description

This function is a no-op for MS-DOS, but is provided to assist in Unix
ports.  @xref{getmntent}.

@subheading Return Value

This function always returns nonzero to signify an error.

@subheading Portability

@portability !ansi, !posix

@c ----------------------------------------------------------------------
@node hasmntopt, unix
@findex hasmntopt
@subheading Syntax

@example
#include <mntent.h>

char *hasmntopt(const struct mntent *mnt, const char *opt);
@end example

@subheading Description

This function scans the @code{mnt_opts} field of the @code{mntent}
structure pointed to by @var{mnt} for a substring that matches
@var{opt}.  @xref{getmntent}.

@subheading Return Value

This function returns the address of the substring if a match is found,
or @code{NULL} otherwise.

@subheading Portability

@portability !ansi, !posix

@c ----------------------------------------------------------------------
@node endmntent, unix
@findex endmntent
@subheading Syntax

@example
#include <mntent.h>

int endmntent(FILE *filep);
@end example

@subheading Description

This function should be called after the last call to @code{getmntent}
(@pxref{getmntent}).

@subheading Return Value

This function always returns one.

@subheading Portability

@portability !ansi, !posix