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Standard C Library Functionsgetmntent(3C)


NAME

 getmntent, getmntany, getextmntent, hasmntopt, putmntent, resetmnttab - get mounted device information

SYNOPSIS

 
#include <stdio.h>
#include <sys/mnttab.h>
int getmntent(FILE *fp, struct mnttab *mp);
 int getmntany(FILE *fp, struct mnttab *mp, struct mnttab *mpref);
 int getextmntent(FILE *fp, struct extmnttab *mp, int len);
 char *hasmntopt(struct mnttab *mnt, char *opt);
 int putmntent(FILE *iop, struct mnttab *mp);
 void resetmnttab(FILE *fp);

DESCRIPTION

 

getmntent and getmntany

 

The getmntent() and getmntany() functions each fill in the structure pointed to by mp with the broken-out fields of a line in the mnttab file. Each line read from the file contains a mnttab structure, which is defined in the <sys/mnttab.h> header. The structure contains the following members, which correspond to the broken-out fields from a line in /etc/mnttab (see mnttab(4)).

 
char   *mnt_special;     /* name of mounted resource */
char   *mnt_mountp;      /* mount point */
char   *mnt_fstype;      /* type of file system mounted */
char   *mnt_mntopts;     /* options for this mount */
char   *mnt_time;        /* time file system mounted */

Each getmntent() call causes a new line to be read from the mnttab file. Successive calls can be used to search the entire list. The getmntany() function searches the file referenced by fp until a match is found between a line in the file and mpref. A match occurs if all non-null entries in mpref match the corresponding fields in the file. Note that these functions do not open, close, or rewind the file.

getextmntent

 

The getextmntent() function is an extended version of the getmntent() function that returns, in addition to the information that getmntent() returns, the major and minor number of the mounted resource to which the line in mnttab corresponds. The getextmntent() function also fills in the extmntent structure defined in the <sys/mnttab.h> header. For getextmntent() to function properly, it must be notified when the mnttab file has been reopened or rewound since a previous getextmntent() call. This notification is accomplished by calling resetmnttab(). Otherwise, it behaves exactly as getmntent() described above

The data pointed to by the mnttab structure members are stored in a static area and must be copied to be saved between successive calls.

hasmntopt

 

The hasmntopt() function scans the mnt_mntopts member of the mnttab structure mnt for a substring that matches opt. It returns the address of the substring if a match is found; otherwise it returns 0. Substrings are delimited by commas and the end of the mnt_mntopts string.

putmntent

 

The putmntent() function is obsolete and no longer has any effect. Entries appear in mnttab as a side effect of a mount(2) call. The function name is still defined for transition purposes.

resetmnttab

 

The resetmnttab() function notifies getextmntent() to reload from the kernel the device information that corresponds to the new snapshot of the mnttab information (see mnttab(4)). Subsequent getextmntent() calls then return correct extmnttab information. This function should be called whenever the mnttab file is either rewound or closed and reopened before any calls are made to getextmntent().

RETURN VALUES

 

getmntent and getmntany

 

If the next entry is successfully read by getmntent() or a match is found with getmntany(), 0 is returned. If an EOF is encountered on reading, these functions return -1. If an error is encountered, a value greater than 0 is returned. The following error values are defined in <sys/mnttab.h>:

MNT_TOOLONG
A line in the file exceeded the internal buffer size of MNT_LINE_MAX.
MNT_TOOMANY
A line in the file contains too many fields.
MNT_TOOFEW
A line in the file contains too few fields.

hasmntopt

 

Upon successful completion, hasmntopt() returns the address of the substring if a match is found. Otherwise, it returns 0.

putmntent

 

The putmntent() is obsolete and always returns -1.

ATTRIBUTES

 

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPEATTRIBUTE VALUE
MT-LevelSafe

SEE ALSO

 

mount(2), mnttab(4), attributes(5)


SunOS 5.9Go To TopLast Changed 10 Aug 1999

 
      
      
Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.