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.\"     @(#)fnmatch.3	8.3 (Berkeley) 4/28/95
.\" $FreeBSD$
.\"
.Dd April 2, 2022
.Dt FNMATCH 3
.Os
.Sh NAME
.Nm fnmatch
.Nd test whether a filename or pathname matches a shell-style pattern
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In fnmatch.h
.Ft int
.Fn fnmatch "const char *pattern" "const char *string" "int flags"
.Sh DESCRIPTION
The
.Fn fnmatch
function
matches patterns according to the rules used by the shell.
It checks the string specified by the
.Fa string
argument to see if it matches the pattern specified by the
.Fa pattern
argument.
.Pp
The
.Fa flags
argument modifies the interpretation of
.Fa pattern
and
.Fa string .
The value of
.Fa flags
is the bitwise inclusive
.Tn OR
of any of the following
constants, which are defined in the include file
.In fnmatch.h .
.Bl -tag -width FNM_PATHNAME
.It Dv FNM_NOESCAPE
Normally, every occurrence of a backslash
.Pq Ql \e
followed by a character in
.Fa pattern
is replaced by that character.
This is done to negate any special meaning for the character.
If the
.Dv FNM_NOESCAPE
flag is set, a backslash character is treated as an ordinary character.
.It Dv FNM_PATHNAME
Slash characters in
.Fa string
must be explicitly matched by slashes in
.Fa pattern .
If this flag is not set, then slashes are treated as regular characters.
.It Dv FNM_PERIOD
Leading periods in
.Fa string
must be explicitly matched by periods in
.Fa pattern .
If this flag is not set, then leading periods are treated as regular
characters.
The definition of
.Dq leading
is related to the specification of
.Dv FNM_PATHNAME .
A period is always
.Dq leading
if it is the first character in
.Fa string .
Additionally, if
.Dv FNM_PATHNAME
is set,
a period is
leading
if it immediately follows a slash.
.It Dv FNM_LEADING_DIR
Ignore
.Dq Li /*
rest after successful
.Fa pattern
matching.
.It Dv FNM_CASEFOLD
Ignore case distinctions in both the
.Fa pattern
and the
.Fa string .
.El
.Sh RETURN VALUES
The
.Fn fnmatch
function returns zero if
.Fa string
matches the pattern specified by
.Fa pattern ,
otherwise, it returns the value
.Dv FNM_NOMATCH .
.Sh SEE ALSO
.Xr sh 1 ,
.Xr glob 3 ,
.Xr regex 3
.Sh STANDARDS
The current implementation of the
.Fn fnmatch
function
.Em does not
conform to
.St -p1003.2 .
Collating symbol expressions, equivalence class expressions and
character class expressions are not supported.
.Sh HISTORY
A predecessor to
.Fn fnmatch ,
.Fn gmatch ,
first appeared in the Programmer's Workbench (PWB/UNIX).
The
.Fn fnmatch
function first appeared in
.Bx 4.4 .
.Sh BUGS
The pattern
.Ql *
matches the empty string, even if
.Dv FNM_PATHNAME
is specified.