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[thirdparty/man-pages.git] / man3 / getfsent.3

.\" Copyright (C) 2002 Andries Brouwer (aeb@cwi.nl)
.\"
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.\" Inspired by a page written by Walter Harms.
.\"
.TH GETFSENT 3 2002-02-28 "GNU" "Linux Programmer's Manual"
.SH NAME
getfsent, getfsspec, getfsfile, setfsent, endfsent \- handle fstab entries
.SH SYNOPSIS
.B #include <fstab.h>
.sp
.B "void endfsent(void);"
.sp
.B "struct fstab *getfsent(void);"
.sp
.BI "struct fstab *getfsfile(const char *" mount_point );
.sp
.BI "struct fstab *getfsspec(const char *" special_file );
.sp
.B "int setfsent(void);"
.SH DESCRIPTION
These functions read from the file
.IR /etc/fstab .
The
.IR "struct fstab"
is defined by:
.LP
.in +4n
.nf
struct fstab {
    char       *fs_spec;       /* block device name */
    char       *fs_file;       /* mount point */
    char       *fs_vfstype;    /* file-sysem type */
    char       *fs_mntops;     /* mount options */
    const char *fs_type;       /* rw/rq/ro/sw/xx option */
    int         fs_freq;       /* dump frequency, in days */
    int         fs_passno;     /* pass number on parallel dump */
};
.fi
.in
.PP
Here the field
.I fs_type
contains (on a *BSD system)
one of the five strings "rw", "rq", "ro", "sw", "xx"
(read-write, read-write with quota, read-only, swap, ignore).

The function
.BR setfsent ()
opens the file when required and positions it at the first line.
.LP
The function
.BR getfsent ()
parses the next line from the file.
(After opening it when required.)
.LP
The function
.BR endfsent ()
closes the file when required.
.LP
The function
.BR getfsspec ()
searches the file from the start and returns the first entry found
for which the
.I fs_spec
field matches the
.I special_file
argument.
.LP
The function
.BR getfsfile ()
searches the file from the start and returns the first entry found
for which the
.I fs_file
field matches the
.I mount_point
argument.
.SH RETURN VALUE
Upon success, the functions
.BR getfsent (),
.BR getfsfile (),
and
.BR getfsspec ()
return a pointer to a
.IR "struct fstab" ,
while
.BR setfsent ()
returns 1.
Upon failure or end-of-file, these functions return NULL and 0, respectively.
.\" .SH HISTORY
.\" The
.\" .BR getfsent ()
.\" function appeared in 4.0BSD; the other four functions appeared in 4.3BSD.
.SH CONFORMING TO
These functions are not in POSIX.1-2001.
Several operating systems have them,
e.g., *BSD, SunOS, Digital UNIX, AIX (which also has a
.BR getfstype ()).
HP-UX has functions of the same names,
that however use a
.IR "struct checklist"
instead of a
.IR "struct fstab" ,
and calls these functions obsolete, superseded by
.BR getmntent (3).
.SH NOTES
These functions are not thread-safe.
.LP
Since Linux allows mounting a block special device in several places,
and since several devices can have the same mount point, where the
last device with a given mount point is the interesting one,
while
.BR getfsfile ()
and
.BR getfsspec ()
only return the first occurrence, these two functions are not suitable
for use under Linux.
.SH SEE ALSO
.BR getmntent (3),
.BR fstab (5)