X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?p=subdirmk.git;a=blobdiff_plain;f=README;h=006b57f62eaeacb6cb0927dcfe67b3968121e15b;hp=ef839d56d9e7669abf3143e172ab0efbcb334f3a;hb=61f8c1504443809e6a86217bc8f35ba9c1b7ab5f;hpb=0a6dd433bf3969cf7dfa6dcfecfc1244a289c0b4 diff --git a/README b/README index ef839d5..006b57f 100644 --- a/README +++ b/README @@ -105,6 +105,19 @@ is already provided in subdirmk, for you to reference like this: &:include subdirmk/clean.sd.mk For example you could put that in Perdir.sd.mk. +The top-level Subdir.sd.mk is the first makefile included after the +autogenerated `main.mk' which merely has some basic settings and +includes. So if you want to get in early and set global variables, +put them near the top of Subdir.sd.mk. + +subdirmk's filter script itself sets (only) these variables: + top_srcdir + abs_top_srcdir + SUBDIRMK_MAKEFILES + MAKEFILE_TEMPLATES +You are likely to want to define $(PWD), and shorter names for +top_srdir and abs_top_srcdir (we suggest $(src) and $(abs_src)). + Global definitions ------------------ @@ -152,30 +165,34 @@ locations: (ii) In (or relative to) the subdirectory to which this Subdir.sd.mk relates, or relative to the project's top level ? - (iii) Absolute or relative pathname ? - (Usually relative pathnames suffice.) + (iii) Absolute or relative pathname ? Usually relative pathnames + suffice. Where an absolute pathname is needed, it can be built + out of &/ and an appropriate make variable such as $(PWD). Path construction &-expansions are built from the following: - Relative paths in... Absolute paths in... - build source build source + Relative paths in... + build source - This directory & &, &@ &@, - Top level . &; &@. &@; + This directory & &^ + Top level . &~ -In more detail, with the various options for what comes next: +In more detail, with all the various options laid out: Recommended Relative paths in... Absolute paths in... - for build source build source + for build source build source - This lc &file &,file &@file &@,file - directory any &/file &,/file &@/file &@,/file - several & f g h &, f g h &@ f g h &@, f g h + This lc &file &^file $(PWD)/&file $(abs_src)/&file + directory any &/file &^/file $(PWD)/&/file $(abs_src)/&/file + several & f g h &^ f g h $(addprefix...) - Top lc file &;file &@.file &@;file - level any file &;/file &@./file &@;/file - several f g h &; f g h &@. f g h &@; f g h - .mk.in file $(src)/file $(abs)/file $(abs_src)/file + Top lc file &~file + level any file &~/file $(PWD)/file $(abs_src)/file + .mk.in file $(src)/file $(PWD)/file $(abs_src)/file + several f g h &~ f g h $(addprefix...) + +(This assumes you have appropriate make variables src, PWD and +abs_src.) Substitution syntax ------------------- @@ -207,38 +224,28 @@ empty string). &/ => sub/dir/ or nothing &=/ => sub/dir or . -&,lc => $(top_srcdir)/sub/dir/lc &,/ => $(top_srcdir)/sub/dir/ -&;lc => $(top_srcdir)/lc &;/ => $(top_srcdir)/ +&^lc => $(top_srcdir)/sub/dir/lc +&^/ => $(top_srcdir)/sub/dir/ -&@lc => $(PWD)/sub/dir/lc &@/ => $(PWD)/sub/dir/ -&@.lc => $(PWD)/lc &@./ => $(PWD)/ -&@,lc => $(abs_top_srcdir)/sub/dir/lc &@,/ => $(abs_top_srcdir)/sub/dir/ -&@;lc => $(abs_top_srcdir)/lc &@;/ => $(abs_top_srcdir)/ +&~lc => $(top_srcdir)/lc +&~/ => $(top_srcdir)/ In general: - = return subdir without delimiter (not allowed with `,' `;' `@') - , pathname of this subdirectory in source tree - ; pathname of top level of source tree - . pathname of this directory in build tree, `@' must be specified - @ absolute pathnames + = return subdir without delimiter (not allowed with `^' `~') + ^ pathname of this subdirectory in source tree + ~ pathname of top level of source tree / terminates the escape (needed if next is not lwsp or space) lwsp starts multi-word processing (see below) So pathname syntax is a subset of: - '&' [ '@' ] [ ',' | ';' | '.' ] [ lc | '/' ] - - To avoid incomprehensible .sd.mk files, some combinations are not - allowed. For example `&=./' would mean `.' and `&./' would be the - empty string. Variations with `=' and one of `@' `,' `;' are - uncommon and must be written using make variables instead. + '&' [ '^' | '~' ] [ lc | '/' ] && => && for convenience in shell runes \& => & general escaping mechanism -& thing thing... & &@ thing thing... & - &. thing thing... & -&, thing thing... & &@, thing thing... & -&; thing thing... & &@; thing thing... & +& thing thing... & +&^ thing thing... & +&~ thing thing... & Convenience syntax for prefixing multiple filenames. Introduced by & followed by lwsp where lc could go. Each lwsp-separated non-ws word is prefixed by &/ etc. @@ -259,11 +266,11 @@ So pathname syntax is a subset of: &# delete everything to end of line (useful if the RHS contains unrecognised & constructions) -&!STUFF +&:changequote STUFF changes the escape sequence from & to literally STUFF STUFF may be any series of of non-whitespace characters, - and is terminated by EOL or lwsp. &!STUFF and the lwsp - are discarded. + and is terminated by EOL or lwsp. The whole line is + discarded. After this, write STUFF instead of &, everywhere. The effect is global and lasts until the next setting. @@ -271,9 +278,9 @@ So pathname syntax is a subset of: it back before using &:include. Notably - STUFFSTUFF => STUFFSTUFF - \STUFF => STUFF - STUFF!& set escape back to & + STUFFSTUFF => STUFFSTUFF + \STUFF => STUFF + STUFF:changequote & => set escape back to & &TARGETS_things Handled specially. If mentioned, declares that this @@ -364,6 +371,13 @@ makefiles, you may find that just `make' is broken now and cannot get far enough to regenerate a working set of makefiles. If this happens just rerun ./config.status by hand. +If you go back and forth between different versions of your code you +can sometimes find that `make' complains that one of your Subdir.sd.mk +files is missing: typically, if iot was used and therefore a +dependency in some other version of your code. If you run `make +clean' (or `make realclean') these dependencies are suppressed, which +will clear up the problem. + Legal information -----------------