The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.
A newer edition of this document exists here


fnmatch - match a filename or a pathname


#include <fnmatch.h>

int fnmatch(const char *
pattern, const char *string, int flags);


The fnmatch() function shall match patterns as described in the Shell and Utilities volume of IEEE Std 1003.1-2001, Section 2.13.1, Patterns Matching a Single Character, and Section 2.13.2, Patterns Matching Multiple Characters. It checks the string specified by the string argument to see if it matches the pattern specified by the pattern argument.

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 IEEE Std 1003.1-2001, Section 2.13.3, Patterns Used for Filename Expansion where the location of "leading" is indicated by the value of FNM_PATHNAME:

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.


No errors are defined.

The following sections are informative.




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 manner.

The name fnmatch() is intended to imply filename match, rather than pathname match. The default action of this function is to match filenames, 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 IEEE Std 1003.1-2001. 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.




glob(), wordexp(), the Base Definitions volume of IEEE Std 1003.1-2001, <fnmatch.h>, the Shell and Utilities volume of IEEE Std 1003.1-2001


First released in Issue 4. Derived from the ISO POSIX-2 standard.

Issue 5

Moved from POSIX2 C-language Binding to BASE.

End of informative text.

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