# $NetBSD: directive-ifndef.mk,v 1.6 2020/10/24 08:46:08 rillig Exp $ # # Tests for the .ifndef directive, which can be used for multiple-inclusion # guards. In contrast to C, where #ifndef and #define nicely line up the # macro name, there is no such syntax in make. Therefore, it is more # common to use .if !defined(GUARD) instead. .ifndef GUARD GUARD= # defined . info guarded section .endif .ifndef GUARD GUARD= # defined . info guarded section .endif .if !defined(GUARD) GUARD= # defined . info guarded section .endif all: @:; |