On Mon, Oct 09, 2017 at 10:27:19AM +0500, ???? ??????? wrote: > 2017-10-09 10:10 GMT+05:00 Vincent Bernat <[email protected]>: > > > ? 9 octobre 2017 08:49 +0500, ???? ??????? <[email protected]> : > > > > >> > any particular reason for mixing "CC=gcc" with "CC?=gcc" ? > > >> > > >> I don't see any use of ?=, except for stuff that are expected to be in > > >> environment variables (like HOME, DISPLAY, LANG, PATH). > > >> > > > > > > # find . -name Makefile -exec grep -E '^CC' {} ';' -print > > > CC = gcc > > > ./Makefile > > > CC = gcc > > > ./contrib/debug/Makefile > > > CC = gcc > > > ./contrib/halog/Makefile > > > CC = gcc > > > ./contrib/ip6range/Makefile > > > CC = gcc > > > ./contrib/iprange/Makefile > > > CC ?= gcc > > > ./contrib/mod_defender/Makefile > > > CC ?= gcc > > > ./contrib/modsecurity/Makefile > > > CC = gcc > > > ./contrib/spoa_example/Makefile > > > CC = gcc > > > ./contrib/tcploop/Makefile > > > > Oh, I didn't understand. I think ?= should just be =. > > > > I'd stay with ?=, but changing all the occurences to "=" is also nice
I really hate "?=" in makefiles. It causes random issues especially when building larger, more complex projects involving scripts and various stuff being passed via the environment. Just take a look at the patches in crosstool-ng just to fix the accidental sleep of certain CFLAGS or PATH elements through many layers of makefile to get an idea. With just "=" there's no such issue. If you want to change a value, you can set it on the command line. For example here's the script I'm using to around 200 times a day during development : #!/bin/sh exec make -j 18 TMPDIR=/dev/shm DISTCC_HOSTS="--localslots_cpp=100 192.168.0.235/100,lzo" PATH=/f/tc/x86_64-gcc47_glibc218-linux-gnu/bin:$PATH CC=/g/public/linux/master/x86_64-gcc47_glibc218-linux-gnu-gcc TARGET=linux2628 CPU=generic CPU_CFLAGS.generic="-O0" ARCH_FLAGS="-pg" DEP= USE_PCRE=1 PCREDIR= SMALL_OPTS="-DBUFSIZE=8030 -DMAXREWRITE=1030" DEFINE="-DSO_MARK=36 -DTCP_USER_TIMEOUT=18 -DTCP_REPAIR=19 -DDEBUG_DONT_SHARE_POOLS -DDEBUG_MEMORY_POOLS" USE_OPENSSL=1 USE_ZLIB=1 USE_LUA=1 LUA_LIB_NAME=lua EXTRA= USE_SLZ=1 SLZ_INC=/g/public/slz/src SLZ_LIB=/g/public/slz USE_ZLIB= USE_NS=1 "$@" Sure it's ugly. And so what ? Just done it once, and never had to patch the makefile nor to wonder why it works in one xterm and produces a different result in another one. Feel free to propose a patch to convert the three "?=" to "=" however :-) Cheers, Willy
