add -n flag to skip calls to underlying filesystem

[unix-history] / usr / src / lib / libc / sys / getfsstat.2

.\" Copyright (c) 1989 The Regents of the University of California.
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.\"
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.\" by the University of California, Berkeley.  The name of the
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.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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.\"	@(#)getfsstat.2	6.2 (Berkeley) %G%
.\"
.TH GETFSSTAT 2 ""
.UC 7
.SH NAME
getfsstat \- get list of all mounted filesystems
.SH SYNOPSIS
.nf
.ft B
#include <sys/types.h>
#include <sys/mount.h>
.LP
.ft B
getfsstat(buf, bufsize)
struct statfs buf[];
size_t bufsize;
.fi
.ft R
.SH DESCRIPTION
.I Getfsstat
returns information about all mounted filesystems.
.I Buf
is a pointer to an array of
.I statfs
structures defined as follows:
.IP
.ta \w'#define\0\0'u +\w'fsid_t\0\0'u +\w'f_mntfromname[MNAMELEN]\0\0'u
.nf
typedef quad fsid_t;
.sp 1
#define MNAMELEN 32	/* length of buffer for returned name */
.sp 1
struct statfs {
	short	f_type;	/* type of filesystem (see below) */
	short	f_flags;	/* copy of mount flags */
	long	f_fsize;	/* fundamental file system block size */
	long	f_bsize;	/* optimal transfer block size */
	long	f_blocks;	/* total data blocks in file system */
	long	f_bfree;	/* free blocks in fs */
	long	f_bavail;	/* free blocks avail to non-superuser */
	long	f_files;	/* total file nodes in file system */
	long	f_ffree;	/* free file nodes in fs */
	fsid_t	f_fsid;	/* file system id */
	long	f_spare[6];	/* spare for later */
	char	f_mntonname[MNAMELEN];	/* directory on which mounted */
	char	f_mntfromname[MNAMELEN];	/* mounted filesystem */
};
/*
 * File system types.
 */
#define	MOUNT_UFS	1
#define	MOUNT_NFS	2
#define	MOUNT_MFS	3
#define	MOUNT_PC	4
.fi
.PP
Fields that are undefined for a particular file system are set to \-1.
The buffer is filled with an array of
.I fsstat
structures, one for each mounted filesystem
up to the size specified by
.I bufsize .
.PP
If
.I buf
is given as zero,
.I getfsstat
returns just the number of mounted filesystems.
.SH RETURN VALUE
Upon successful completion, the number of 
.I fsstat
structures is returned.
Otherwise, \-1 is returned and the global variable
.I errno
is set to indicate the error.
.SH ERRORS
.I Getfsstat
fails if one or more of the following are true:
.TP 15
EFAULT
.I Buf
points to an invalid address.
.TP 15
EIO
An I/O error occurred while reading from or writing to the file system.
.SH "SEE ALSO"
statfs(2)