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getfsent(3) Library Functions Manual getfsent(3)


getfsent, getfsspec, getfsfile, setfsent, endfsent - handle fstab entries


Standard C library (libc, -lc)


#include <fstab.h>
int setfsent(void);
struct fstab *getfsent(void);
void endfsent(void);
struct fstab *getfsfile(const char *mount_point);
struct fstab *getfsspec(const char *special_file);


These functions read from the file /etc/fstab. The struct fstab is defined by:

struct fstab {

char *fs_spec; /* block device name */
char *fs_file; /* mount point */
char *fs_vfstype; /* filesystem 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 */ };

Here the field 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 setfsent() opens the file when required and positions it at the first line.

The function getfsent() parses the next line from the file. (After opening it when required.)

The function endfsent() closes the file when required.

The function getfsspec() searches the file from the start and returns the first entry found for which the fs_spec field matches the special_file argument.

The function getfsfile() searches the file from the start and returns the first entry found for which the fs_file field matches the mount_point argument.


Upon success, the functions getfsent(), getfsfile(), and getfsspec() return a pointer to a struct fstab, while setfsent() returns 1. Upon failure or end-of-file, these functions return NULL and 0, respectively.


For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
endfsent (), setfsent () Thread safety MT-Unsafe race:fsent
getfsent (), getfsspec (), getfsfile () Thread safety MT-Unsafe race:fsent locale


These functions are not in POSIX.1. Several operating systems have them, for example, *BSD, SunOS, Digital UNIX, AIX (which also has a getfstype()). HP-UX has functions of the same names, that however use a struct checklist instead of a struct fstab, and calls these functions obsolete, superseded by getmntent(3).


These functions are not thread-safe.

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 getfsfile() and getfsspec() only return the first occurrence, these two functions are not suitable for use under Linux.


getmntent(3), fstab(5)

2022-12-15 Linux man-pages 6.03