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home | helpx minix x x minixx GETMNTENT(3) Linux Programmer's Manual GETMNTENT(3) NAME getmntent, setmntent, addmntent, endmntent, hasmntopt, getmntent_r - get filesystem descriptor file entry SYNOPSIS #include <stdio.h> #include <mntent.h> FILE *setmntent(const char *filename, const char *type); struct mntent *getmntent(FILE *stream); int addmntent(FILE *stream, const struct mntent *mnt); int endmntent(FILE *streamp); char *hasmntopt(const struct mntent *mnt, const char *opt); /* GNU extension */ #include <mntent.h> struct mntent *getmntent_r(FILE *streamp, struct mntent *mntbuf, char *buf, int buflen); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): getmntent_r(): Since glibc 2.19: _DEFAULT_SOURCE Glibc 2.19 and earlier: _BSD_SOURCE || _SVID_SOURCE DESCRIPTION These routines are used to access the filesystem description file /etc/fstab and the mounted filesystem description file /etc/mtab. The setmntent() function opens the filesystem description file filename and returns a file pointer which can be used by getmntent(). The argu- ment type is the type of access required and can take the same values as the mode argument of fopen(3). The returned stream should be closed using endmntent() rather than fclose(3). The getmntent() function reads the next line of the filesystem descrip- tion file from stream and returns a pointer to a structure containing the broken out fields from a line in the file. The pointer points to a static area of memory which is overwritten by subsequent calls to getm- ntent(). The addmntent() function adds the mntent structure mnt to the end of the open stream. The endmntent() function closes the stream associated with the filesys- tem description file. The hasmntopt() function scans the mnt_opts field (see below) of the mntent structure mnt for a substring that matches opt. See _mntent.h_ and mount(8) for valid mount options. The reentrant getmntent_r() function is similar to getmntent(), but stores the struct mount in the provided *mntbuf and stores the strings pointed to by the entries in that struct in the provided array buf of size buflen. The mntent structure is defined in _mntent.h_ as follows: struct mntent { char *mnt_fsname; /* name of mounted filesystem */ char *mnt_dir; /* filesystem path prefix */ char *mnt_type; /* mount type (see mntent.h) */ char *mnt_opts; /* mount options (see mntent.h) */ int mnt_freq; /* dump frequency in days */ int mnt_passno; /* pass number on parallel fsck */ }; Since fields in the mtab and fstab files are separated by whitespace, octal escapes are used to represent the characters space (\040), tab (\011), newline (\012), and backslash (\\) in those files when they oc- cur in one of the four strings in a mntent structure. The routines ad- dmntent() and getmntent() will convert from string representation to escaped representation and back. When converting from escaped repre- sentation, the sequence \134 is also converted to a backslash. RETURN VALUE The getmntent() and getmntent_r() functions return a pointer to the mn- tent structure or NULL on failure. The addmntent() function returns 0 on success and 1 on failure. The endmntent() function always returns 1. The hasmntopt() function returns the address of the substring if a match is found and NULL otherwise. FILES /etc/fstab filesystem description file /etc/mtab mounted filesystem description file ATTRIBUTES For an explanation of the terms used in this section, see at- tributes(7). +--------------+---------------+---------------------------------+ |Interface | Attribute | Value | +--------------+---------------+---------------------------------+ |setmntent(), | Thread safety | MT-Safe | |endmntent(), | | | |hasmntopt() | | | +--------------+---------------+---------------------------------+ |getmntent() | Thread safety | MT-Unsafe race:mntentbuf locale | +--------------+---------------+---------------------------------+ |addmntent() | Thread safety | MT-Safe race:stream locale | +--------------+---------------+---------------------------------+ |getmntent_r() | Thread safety | MT-Safe locale | +--------------+---------------+---------------------------------+ CONFORMING TO The nonreentrant functions are from SunOS 4.1.3. A routine getmn- tent_r() was introduced in HP-UX 10, but it returns an int. The proto- type shown above is glibc-only. NOTES System V also has a getmntent() function but the calling sequence dif- fers, and the returned structure is different. Under System V /etc/mnttab is used. 4.4BSD and Digital UNIX have a routine getm- ntinfo(), a wrapper around the system call getfsstat(). SEE ALSO fopen(3), fstab(5), mount(8) COLOPHON This page is part of release 5.05 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. 2019-03-06 GETMNTENT(3)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | FILES | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON