varname-dot-newline.mk revision 1.6 1 # $NetBSD: varname-dot-newline.mk,v 1.6 2023/01/26 20:48:18 sjg Exp $
2 #
3 # Tests for the special .newline variable, which contains a single newline
4 # character (U+000A).
5
6
7 # https://austingroupbugs.net/view.php?id=1549 proposes:
8 # > After all macro expansion is complete, when an escaped <newline> is
9 # > found in a command line in a makefile, the command line that is executed
10 # > shall contain the <backslash>, the <newline>, and the next line, except
11 # > that the first character of the next line shall not be included if it is
12 # > a <tab>.
13 #
14 # The above quote assumes that each resulting <newline> character has a "next
15 # line", but that's not how the .newline variable works.
16 BACKSLASH_NEWLINE:= \${.newline}
17
18
19 # Check that .newline is read-only
20
21 NEWLINE:= ${.newline}
22
23 .newline= overwritten
24
25 .if ${.newline} != ${NEWLINE}
26 . error The .newline variable can be overwritten. It should be read-only.
27 .endif
28
29 all:
30 @echo 'first${.newline}second'
31 @echo 'backslash newline: <${BACKSLASH_NEWLINE}>'
32