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
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_PATHNAME is set, a period is "leading" if
it is the first character in string or if it immediately follows a
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
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 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.
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html