.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) .\" .\" %%%LICENSE_START(VERBATIM) .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one. .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" %%%LICENSE_END .\" .\" References consulted: .\" Linux libc source code .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) .\" 386BSD man pages .\" Modified Sat Jul 24 21:46:57 1993 by Rik Faith (faith@cs.unc.edu) .\" Modified 961109, 031115, aeb .\" .TH GETMNTENT 3 2017-03-13 "" "Linux Programmer's Manual" .SH NAME getmntent, setmntent, addmntent, endmntent, hasmntopt, getmntent_r \- get filesystem descriptor file entry .SH SYNOPSIS .nf .B #include .B #include .sp .BI "FILE *setmntent(const char *" filename ", const char *" type ); .sp .BI "struct mntent *getmntent(FILE *" stream ); .sp .BI "int addmntent(FILE *" stream ", const struct mntent *" mnt ); .sp .BI "int endmntent(FILE *" streamp ); .sp .BI "char *hasmntopt(const struct mntent *" mnt ", const char *" opt ); .sp /* GNU extension */ .B #include .sp .BI "struct mntent *getmntent_r(FILE *" streamp ", struct mntent *" mntbuf , .BI " char *" buf ", int " buflen ); .fi .sp .in -4n Feature Test Macro Requirements for glibc (see .BR feature_test_macros (7)): .in .sp .BR getmntent_r (): Since glibc 2.19: _DEFAULT_SOURCE Glibc 2.19 and earlier: _BSD_SOURCE || _SVID_SOURCE .SH DESCRIPTION These routines are used to access the filesystem description file .I /etc/fstab and the mounted filesystem description file .IR /etc/mtab . .PP The .BR setmntent () function opens the filesystem description file .I filename and returns a file pointer which can be used by .BR getmntent (). The argument .I type is the type of access required and can take the same values as the .I mode argument of .BR fopen (3). .PP The .BR getmntent () function reads the next line of the filesystem description file from .I 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 .BR getmntent (). .PP The .BR addmntent () function adds the .I mntent structure .I mnt to the end of the open .IR stream . .PP The .BR endmntent () function closes the .IR stream associated with the filesystem description file. .PP The .BR hasmntopt () function scans the .I mnt_opts field (see below) of the .I mntent structure .I mnt for a substring that matches .IR opt . See .I and .BR mount (8) for valid mount options. .PP The reentrant .BR getmntent_r () function is similar to .BR getmntent (), but stores the .IR "struct mount" in the provided .I *mntbuf and stores the strings pointed to by the entries in that struct in the provided array .I buf of size .IR buflen . .PP The .I mntent structure is defined in .I as follows: .sp .in +4n .nf 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 */ }; .fi .in Since fields in the mtab and fstab files are separated by whitespace, octal escapes are used to represent the characters space (\e040), tab (\e011), newline (\e012), and backslash (\e\e) in those files when they occur in one of the four strings in a .I mntent structure. The routines .BR addmntent () and .BR getmntent () will convert from string representation to escaped representation and back. When converting from escaped representation, the sequence \e134 is also converted to a backslash. .SH RETURN VALUE The .BR getmntent () and .BR getmntent_r () functions return a pointer to the .I mntent structure or NULL on failure. .PP The .BR addmntent () function returns 0 on success and 1 on failure. .PP The .BR endmntent () function always returns 1. .PP The .BR hasmntopt () function returns the address of the substring if a match is found and NULL otherwise. .SH FILES .nf /etc/fstab filesystem description file /etc/mtab mounted filesystem description file .fi .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). .ad l .TS allbox; lbw13 lb lbw31 l l l. Interface Attribute Value T{ .BR setmntent (), .BR endmntent (), .BR hasmntopt () T} Thread safety MT-Safe T{ .BR getmntent () T} Thread safety MT-Unsafe race:mntentbuf locale T{ .BR addmntent () T} Thread safety MT-Safe race:stream locale T{ .BR getmntent_r () T} Thread safety MT-Safe locale .TE .ad .SH CONFORMING TO The nonreentrant functions are from SunOS 4.1.3. A routine .BR getmntent_r () was introduced in HP-UX 10, but it returns an int. The prototype shown above is glibc-only. .SH NOTES System V also has a .BR getmntent () function but the calling sequence differs, and the returned structure is different. Under System V .I /etc/mnttab is used. 4.4BSD and Digital UNIX have a routine .BR getmntinfo (), a wrapper around the system call .BR getfsstat (). .SH SEE ALSO .BR fopen (3), .BR fstab (5), .BR mount (8) .SH COLOPHON This page is part of release 4.10 of the Linux .I 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/.