This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
The fnmatch() function shall match patterns as described in the Shell
and Utilities volume of POSIX.1‐2008, Section 2.13.1, PatternsMatching a Single Character and Section 2.13.2, Patterns MatchingMultiple Characters. It checks the string specified by the string
argument to see if it matches the pattern specified by the pattern
The flags argument shall modify the interpretation of pattern and
string. It is the bitwise-inclusive OR of zero or more of the flags
defined in <fnmatch.h>. If the FNM_PATHNAME flag is set in flags,
then a <slash> character ('/') in string shall be explicitly matched
by a <slash> in pattern; it shall not be matched by either the
<asterisk> or <question-mark> special characters, nor by a bracket
expression. If the FNM_PATHNAME flag is not set, the <slash>
character shall be treated as an ordinary character.
If FNM_NOESCAPE is not set in flags, a <backslash> character in
pattern followed by any other character shall match that second
character in string. In particular, "\\" shall match a <backslash>
in string. If FNM_NOESCAPE is set, a <backslash> character shall be
treated as an ordinary character.
If FNM_PERIOD is set in flags, then a leading <period> ('.') in
string shall match a <period> in pattern; as described by rule 2 in
the Shell and Utilities volume of POSIX.1‐2008, Section 2.13.3,
Patterns Used for Filename Expansion where the location of
``leading'' is indicated by the value of FNM_PATHNAME:
* If FNM_PATHNAME is set, a <period> is ``leading'' if it is the
first character in string or if it immediately follows a <slash>.
* If FNM_PATHNAME is not set, a <period> is ``leading'' only if it
is the first character of string.
If FNM_PERIOD is not set, then no special restrictions are placed on
matching a period.
If string matches the pattern specified by pattern, then fnmatch()
shall return 0. If there is no match, fnmatch() shall return
FNM_NOMATCH, which is defined in <fnmatch.h>. If an error occurs,
fnmatch() shall return another non-zero value.
The fnmatch() function has two major uses. It could be used by an
application or utility that needs to read a directory and apply a
pattern against each entry. The find utility is an example of this.
It can also be used by the pax utility to process its pattern
operands, or by applications that need to match strings in a similar
The name fnmatch() is intended to imply filename match, rather than
pathname match. The default action of this function is to match
filename strings, rather than pathnames, since it gives no special
significance to the <slash> character. With the FNM_PATHNAME flag,
fnmatch() does match pathnames, but without tilde expansion,
parameter expansion, or special treatment for a <period> at the
beginning of a filename.
This function replaced the REG_FILENAME flag of regcomp() in early
proposals of this volume of POSIX.1‐2008. It provides virtually the
same functionality as the regcomp() and regexec() functions using the
REG_FILENAME and REG_FSLASH flags (the REG_FSLASH flag was proposed
for regcomp(), and would have had the opposite effect from
FNM_PATHNAME), but with a simpler function and less system overhead.
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
IEEE/The Open Group 2013 FNMATCH(3P)