On Mon, 2023-07-10 at 17:17 -0400, Jeffrey Walton wrote: > Yes, lots of conditionals and lots of shell'ing, like: > > GREP ?= grep > SED ?= sed > > ifneq ($(wildcard /usr/xpg4/bin/grep),) > GREP := /usr/xpg4/bin/grep > endif > ifneq ($(wildcard /usr/xpg4/bin/sed),) > SED := /usr/xpg4/bin/sed > endif > > SUN_COMPILER := $(shell $(CXX) -V 2>&1 | $(GREP) -i -c -E 'CC: > (Sun|Studio)') > GCC_COMPILER := $(shell $(CXX) --version 2>/dev/null | $(GREP) -v -E > '(llvm|clang)' | $(GREP) -i -c -E '(gcc|g\+\+)') > XLC_COMPILER := $(shell $(CXX) -qversion 2>/dev/null |$(GREP) -i -c > "IBM XL") > CLANG_COMPILER := $(shell $(CXX) --version 2>/dev/null | $(GREP) -i - > c > -E '(llvm|clang)') > INTEL_COMPILER := $(shell $(CXX) --version 2>/dev/null | $(GREP) -i - > c > '\(icc\)') > ...
But, what about this do you want to know? If what you want to know is "what was the result of all this", the database print (-p) option will show you what make computed as the final value for each of these variables, and also what linenumber of the makefile was used to set the final version: # makefile (from 'Makefile', line 12) GCC_COMPILER := 0 ... # makefile (from 'Makefile', line 1) GREP = grep ... I don't want to suggest that everything is just peachy. There are lots of rough edges for working with GNU Make and Makefiles, there is no question about that. I'm just trying to understand clearly what things will actually be useful, rather than simply spewing out more output similar to what -d does. I do agree with Bruno that there is a lot of implicit knowledge for working with Makefiles that is not well described, or in some cases even hinted at, in the manual. Maybe I'll try to add a new chapter this weekend... writing will be a nice change from hacking. I've spent enough time on StackOverflow that I have a good idea of the places people have troubles.
