.TH #undef "" "" "Preprocessing Directive"
.II "macro, undefine"
.II "undefine a macro"
.PC "Undefine a macro"
\fB#undef \fIidentifier\fR
.PP
The preprocessing directive
.B #undef
tells the C preprocessor to disregard
.I identifier
as a macro.
It undoes the effect of the
.B #define
directive.
.fi
.SH "See Also"
.Xr "#define," _23define
.Xr "C preprocessor" c_preproc
.br
\*(AS, \(sc6.8.3
