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NAME |LIBRARY |SYNOPSIS |DESCRIPTION |RETURN VALUE |FILES |ATTRIBUTES |STANDARDS |HISTORY |SEE ALSO |COLOPHON | |
getmntent(3) Library Functions Manualgetmntent(3)getmntent, setmntent, addmntent, endmntent, hasmntopt, getmntent_r - get filesystem descriptor file entry
Standard C library (libc,-lc)
#include <stdio.h>#include <mntent.h>FILE *setmntent(const char *path, const char *type);struct mntent *getmntent(FILE *stream);int addmntent(FILE *restrictstream,const struct mntent *restrictmnt);int endmntent(FILE *streamp);char *hasmntopt(const struct mntent *mnt, const char *opt); /* GNU extension */#include <mntent.h>struct mntent *getmntent_r(int size;FILE *restrictstreamp,struct mntent *restrictmntbuf,charbuf[restrictsize], intsize); Feature Test Macro Requirements for glibc (seefeature_test_macros(7)):getmntent_r(): Since glibc 2.19: _DEFAULT_SOURCE glibc 2.19 and earlier: _BSD_SOURCE || _SVID_SOURCE
These routines are used to access the filesystem description file/etc/fstab and the mounted filesystem description file/etc/mtab. Thesetmntent() function opens the filesystem description filepath and returns a file pointer which can be used bygetmntent(). The argumenttype is the type of access required and can take the same values as themode argument offopen(3). The returned stream should be closed usingendmntent() rather thanfclose(3). Thegetmntent() function reads the next line of the filesystem description file fromstream 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 togetmntent(). Theaddmntent() function adds themntent structuremnt to the end of the openstream. Theendmntent() function closes thestream associated with the filesystem description file. Thehasmntopt() function scans themnt_opts field (see below) of themntent structuremnt for a substring that matchesopt. See<mntent.h> andmount(8) for valid mount options. The reentrantgetmntent_r() function is similar togetmntent(), but stores themntent structure in the provided*mntbuf, and stores the strings pointed to by the entries in that structure in the provided arraybuf of sizesize. Themntent 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 occur in one of the four strings in amntent structure. The routinesaddmntent() andgetmntent() will convert from string representation to escaped representation and back. When converting from escaped representation, the sequence \134 is also converted to a backslash.Thegetmntent() andgetmntent_r() functions return a pointer to themntent structure or NULL on failure. Theaddmntent() function returns 0 on success and 1 on failure. Theendmntent() function always returns 1. Thehasmntopt() function returns the address of the substring if a match is found and NULL otherwise.
/etc/fstab filesystem description file/etc/mtab mounted filesystem description file
For an explanation of the terms used in this section, seeattributes(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 │ └───────────────┴───────────────┴────────────────────────────────┘
None.
The nonreentrant functions are from SunOS 4.1.3. A routinegetmntent_r() was introduced in HP-UX 10, but it returns anint. The prototype shown above is glibc-only. System V also has agetmntent() function but the calling sequence differs, and the returned structure is different. Under System V/etc/mnttab is used. 4.4BSD and Digital UNIX have a routinegetmntinfo(), a wrapper around the system callgetfsstat().
fopen(3),fstab(5),mount(8)
This page is part of theman-pages (Linux kernel and C library user-space interface documentation) project. Information about the project can be found at ⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report for this manual page, see ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩. This page was obtained from the tarball man-pages-6.15.tar.gz fetched from ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on 2025-08-11. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up- to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.orgLinux man-pages 6.15 2025-06-28getmntent(3)Pages that refer to this page:getfsent(3), fstab(5)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |