The GNU C Library - Wildcard Matching

Wildcard Matching

This section describes how to match a wildcard pattern against a particular string. The result is a yes or no answer: does the string fit the pattern or not. The symbols described here are all declared in `fnmatch.h'.

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

This function tests whether the string string matches the pattern pattern. It returns 0 if they do match; otherwise, it returns the nonzero value FNM_NOMATCH . The arguments pattern and string are both strings.

The argument flags is a combination of flag bits that alter the details of matching. See below for a list of the defined flags.

In the GNU C Library, fnmatch cannot experience an ``error''---it always returns an answer for whether the match succeeds. However, other implementations of fnmatch might sometimes report ``errors''. They would do so by returning nonzero values that are not equal to FNM_NOMATCH .

These are the available flags for the flags argument:

FNM_FILE_NAME

Treat the `/' character specially, for matching file names. If this flag is set, wildcard constructs in pattern cannot match `/' in string. Thus, the only way to match `/' is with an explicit `/' in pattern.

FNM_PATHNAME

This is an alias for FNM_FILE_NAME ; it comes from POSIX.2. We don't recommend this name because we don't use the term ``pathname'' for file names.

FNM_PERIOD

Treat the `.' character specially if it appears at the beginning of string. If this flag is set, wildcard constructs in pattern cannot match `.' as the first character of string.

If you set both FNM_PERIOD and FNM_FILE_NAME , then the special treatment applies to `.' following `/' as well as to `.' at the beginning of string. (The shell uses the FNM_PERIOD and FNM_FILE_NAME falgs together for matching file names.)

FNM_NOESCAPE

Don't treat the `\' character specially in patterns. Normally, `\' quotes the following character, turning off its special meaning (if any) so that it matches only itself. When quoting is enabled, the pattern `\?' matches only the string `?', because the question mark in the pattern acts like an ordinary character.

If you use FNM_NOESCAPE , then `\' is an ordinary character.

FNM_LEADING_DIR

Ignore a trailing sequence of characters starting with a `/' in string; that is to say, test whether string starts with a directory name that pattern matches.

If this flag is set, either `foo*' or `foobar' as a pattern would match the string `foobar/frobozz'.

FNM_CASEFOLD

Ignore case in comparing string to pattern.