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Diffstat (limited to 'doc/make.texi')
| -rw-r--r-- | doc/make.texi | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/doc/make.texi b/doc/make.texi index 9a13b78..291a294 100644 --- a/doc/make.texi +++ b/doc/make.texi @@ -149,6 +149,7 @@ Writing Makefiles * Include:: How one makefile can use another makefile. * MAKEFILES Variable:: The environment can specify extra makefiles. * MAKEFILE_LIST Variable:: Discover which makefiles have been read. +* Special Variables:: Other special variables. * Remaking Makefiles:: How makefiles get remade. * Overriding Makefiles:: How to override part of one makefile with another makefile. @@ -929,6 +930,7 @@ reading a data base called the @dfn{makefile}. * Include:: How one makefile can use another makefile. * MAKEFILES Variable:: The environment can specify extra makefiles. * MAKEFILE_LIST Variable:: Discover which makefiles have been read. +* Special Variables:: Other special variables. * Remaking Makefiles:: How makefiles get remade. * Overriding Makefiles:: How to override part of one makefile with another makefile. @@ -1184,7 +1186,7 @@ This is a very bad idea, because such makefiles will fail to work if run by anyone else. It is much better to write explicit @code{include} directives in the makefiles. @xref{Include, , Including Other Makefiles}. -@node MAKEFILE_LIST Variable, Remaking Makefiles, MAKEFILES Variable, Makefiles +@node MAKEFILE_LIST Variable, Special Variables, MAKEFILES Variable, Makefiles @comment node-name, next, previous, up @section The Variable @code{MAKEFILE_LIST} @cindex makefiles, and @code{MAKEFILE_LIST} variable @@ -1232,7 +1234,37 @@ name2 = inc.mk Variables}, for more information on simply-expanded (@code{:=}) variable definitions. -@node Remaking Makefiles, Overriding Makefiles, MAKEFILE_LIST Variable, Makefiles +@node Special Variables, Remaking Makefiles, MAKEFILE_LIST Variable, Makefiles +@comment node-name, next, previous, up +@section Other Special Variables +@cindex makefiles, and special variables +@cindex special variables + +GNU @code{make} also supports two other special variables. Note that +any value you assign to these variables will be ignored; they will +always return their special value. + +@vindex $(.VARIABLES) +@vindex .VARIABLES @r{(list of variables)} +The first special variable is @code{.VARIABLES}. When expanded, the +value consists of a list of the @emph{names} of all global variables +defined in all makefiles read up until that point. This includes +variables which have empty values, as well as built-in variables +(@pxref{Implicit Variables, , Variables Used by Implicit Rules}), but +does not include any variables which are only defined in a +target-specific context. + +@vindex $(.TARGETS) +@vindex .TARGETS @r{(list of targets)} +The second special variable is @code{.TARGETS}. When expanded, the +value consists of a list of all targets defined in all makefiles read +up until that point. Note it's not enough for a file to be simply +mentioned in the makefile to be listed in this variable, even if it +would match an implicit rule and become an ``implicit target''. The +file must appear as a target, on the left-hand side of a ``:'', to be +considered a target for the purposes of this variable. + +@node Remaking Makefiles, Overriding Makefiles, Special Variables, Makefiles @section How Makefiles Are Remade @cindex updating makefiles |