getfsent.3x

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)getfsent.3x	8.1	9/11/90
.TH getfsent 3x
.SH Name
getfsent, getfsspec, getfsfile, getfstype, setfsent, endfsent \- get file system descriptor file entry
.SH Syntax
.nf
.B #include <fstab.h>
.B #include "/usr/include/sys/fs_types.h"
.PP
.B struct fstab *getfsent()
.PP
.B struct fstab *getfsspec(\fIspec\fP)
.B char *\fIspec\fP;
.PP
.B struct fstab *getfsfile(\fIfile\fP)
.B char *\fIfile\fP;
.PP
.B struct fstab *getfstype(\fItype\fP)
.B char *\fItype\fP;
.PP
.B int setfsent()
.PP
.B int endfsent()
.fi
.SH Description
.NXR "getfsent subroutine"
.NXR "getfsspec subroutine"
.NXR "getfsfile subroutine"
.NXR "getfstype subroutine"
.NXR "setfsent subroutine"
.NXR "endfsent subroutine"
.NXR "fstab file" "getting entry"
.NXR "fstab file" "setting"
.NXR "fstab file" "closing"
.NXR "fstab file" "getting special file name"
.NXR "fstab file" "getting file system name"
.NXR "fstab file" "getting file system type"
.NXA "fstab file" "getfsent subroutine"
All routines operate on the file 
.PN /etc/fstab ,
which contains
descriptions of the known file systems.
The routine
.PN setfsent
opens this file.  The routine
.PN getfsent
reads the next file system description 
within 
.PN /etc/fstab
opening the file if necessary.  
The
.PN endfsent 
routine closes the file.
.PP
The
.PN getfsspec ,
.PN getfsfile ,
and
.PN getfstype
routines
sequentially scan the file 
.PN /etc/fstab
for specific file system descriptions.  
The
.PN getfsspec
routine searches for a description 
with a matching special file name field. 
The routine
.PN getfsfile
searches for a description 
with a matching file system path prefix field.
The routine
.PN getfstype
searches for a description with a matching file system type field.
.PP
The
.PN getfsent ,
.PN getfsspec ,
.PN getfstype, 
and
.PN getfsfile
each
return a pointer to a representation of the description they have
matched or read.
Representations are in the format of the following structure:
.EX
#define	FSTAB_RW	"rw"	/* read-write device      */
#define	FSTAB_RO	"ro"	/* read-only device       */
#define	FSTAB_RQ	"rq"	/* read-write with quotas */
#define	FSTAB_SW	"sw"	/* swap device            */
#define	FSTAB_XX	"xx"	/* ignore totally         */

struct fstab {
	char	*fs_spec;	/* block special device name    */
	char	*fs_file;	/* file system path prefix      */
	char	*fs_type;	/* rw,ro,sw or xx               */
	int	fs_freq;	/* dump frequency, in days      */
	int	fs_passno;	/* pass number on parallel dump */
	char	*fs_name;	/* name of the file system type */
	char	*fs_opts	/* arbitrary options field      */
};
.EE
.SH Return Values
A NULL or 0 is returned, but 
.I errno
is not set
on detection of errors.
.SH Restrictions 
All descriptions are contained in
static areas, which should be copied. 
.SH Files
.TP 15
/etc/fstab
File system information file.
.SH See Also
fstab(5)