X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?p=subdirmk.git;a=blobdiff_plain;f=README;h=63e41881b9674d440978d4f1076190f2df7fef3d;hp=c9e4c0f9234f2fe42bac8187dd98c88784bb417a;hb=cf7f7e9dfdb0241d091655bca63edcdae5b81c03;hpb=0a6ac67828982aca4e3c8ac73669420a30c70f34 diff --git a/README b/README index c9e4c0f..63e4188 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 ------------------ @@ -161,22 +174,22 @@ Path construction &-expansions are built from the following: Relative paths in... build source - This directory & &, - Top level . &; + This directory & &^ + Top level . &~ In more detail, with all the various options laid out: Recommended Relative paths in... Absolute paths in... for build source build source - 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...) + 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 - level any file &;/file $(PWD)/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...) + several f g h &~ f g h $(addprefix...) (This assumes you have appropriate make variables src, PWD and abs_src.) @@ -205,34 +218,45 @@ empty string). The assumption is that filenames are usually lowercase and variables usually uppercase. Otherwise, use another syntax: +&/ => sub/dir/ or nothing &_ => sub_dir_ or TOP_ -&=_ => sub_dir or TOP +&. => sub/dir or . + (This implies that `&./' works roughly like `&/', although + it can produce a needless `./') -&/ => sub/dir/ or nothing -&=/ => sub/dir or . +&= => sub_dir or TOP -&,lc => $(top_srcdir)/sub/dir/lc -&,/ => $(top_srcdir)/sub/dir/ +&^lc => $(top_srcdir)/sub/dir/lc +&^/ => $(top_srcdir)/sub/dir/ +&^. => $(top_srcdir)/sub/dir -&;lc => $(top_srcdir)/lc -&;/ => $(top_srcdir)/ +&~lc => $(top_srcdir)/lc +&~/ => $(top_srcdir)/ +&~. => $(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 - / terminates the escape (needed if next is not lwsp or space) + ^ pathname of this subdirectory in source tree + ~ pathname of top level of source tree + / terminates the path escape } needed if next is + _ terminates the var escape } not lwsp or space) + . terminates path escape giving dir name (excluding /) + = terminates var escape giving only prefix part (rarely needed) lwsp starts multi-word processing (see below) So pathname syntax is a subset of: - '&' [ ',' | ';' ] [ lc | '/' ] + '&' [ '^' | '~' ] [ lc | '/' | '.' | '=' ] && => && for convenience in shell runes -\& => & general escaping mechanism + +&\& => & general escaping mechanism +&\$ => $ + +&$VARIABLE => $(sub_dir_VARIABLE) or $(TOP_VARIABLE) + VARIABLE is ASCII starting with a letter and matching \w+ & 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. @@ -244,30 +268,31 @@ So pathname syntax is a subset of: recognised at start of line only (possibly after lwsp) args are processed for & -&:include filename filename should usually be foo.sd.mk +&:include filename filename should usually be [&]foo.sd.mk &:-include filename tolerate nonexistent file filenames are relative to $(top_srcdir) + RHS is &-expanded &! disables & until EOL (and then disappears) &# delete everything to end of line (useful if the RHS contains unrecognised & constructions) -&!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. +&:changequote NEWQUOTE + changes the escape sequence from & to literally NEWQUOTE + NEWQUOTE may be any series of of non-whitespace characters, + and is terminated by EOL or lwsp. The whole line is + discarded. - After this, write STUFF instead of &, everywhere. + After this, write NEWQUOTE instead of &, everywhere. The effect is global and lasts until the next setting. It takes effect on &:include'd files too, so maybe set it back before using &:include. Notably - STUFFSTUFF => STUFFSTUFF - \STUFF => STUFF - STUFF!& set escape back to & + NEWQUOTENEWQUOTE => NEWQUOTENEWQUOTE + NEWQUOTE\NEWQUOTE => NEWQUOTE + NEWQUOTE:changequote & set escape back to & &TARGETS_things Handled specially. If mentioned, declares that this @@ -358,6 +383,13 @@ 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 -----------------