# configure: -lpthread doesn't belong in CFLAGS 7 messages from 2015-11-01 to 2015-11-20. Participants: Rainer M. Canavan, Matthieu Moy, Jeff King. Thread: https://gitlist.dev/t/40701 ## Rainer M. Canavan, 2015-11-01 22:30 Subject: configure: -lpthread doesn't belong in CFLAGS Message-ID: <201511012230.tA1MUGa5016836@tezro.nonet> URL: https://gitlist.dev/e/201511012230.tA1MUGa5016836%40tezro.nonet ``` Hi, some linkers, namely the one on IRIX are rather strict concerning the order or arguments for symbol resolution, i.e. no libraries listed before objects or other libraries on the command line are considered for symbol resolution. That means that -lpthread can't work if it's put in CFLAGS, because it will not be considered for resolving pthread_key_create in conftest.o. Apparently only $LIBS goes after conftest.o when the linker is called. Without the patch below, the POSIX Threads with '-lpthread' fails, with the patch it succeeds. I haven't checked if that is relevant at all, since that check is immediately followed by checking for pthread_create in -lpthread... yes regards, rainer --- ../src/git-2.6.2/configure.ac Fri Oct 16 23:58:26 CEST 2015 +++ configure.ac Sun Nov 01 23:19:41 CET 2015 @@ -1126,7 +1126,13 @@ # would then trigger compiler warnings on every single file we compile. for opt in "" -mt -pthread -lpthread; do old_CFLAGS="$CFLAGS" - CFLAGS="$opt $CFLAGS" + old_LIBS="$LIBS" + if test "$(echo $opt | cut -b 1-2)" = -l ; then + LIBS="$opt $LIBS" + else + CFLAGS="$opt $CFLAGS" + fi + AC_MSG_CHECKING([for POSIX Threads with '$opt']) AC_LINK_IFELSE([PTHREADTEST_SRC], [AC_MSG_RESULT([yes]) @@ -1138,6 +1144,7 @@ ], [AC_MSG_RESULT([no])]) CFLAGS="$old_CFLAGS" + LIBS="$old_LIBS" done if test $threads_found != yes; then AC_CHECK_LIB([pthread], [pthread_create], ``` ## Matthieu Moy, 2015-11-02 08:27 Subject: Re: configure: -lpthread doesn't belong in CFLAGS Message-ID: URL: https://gitlist.dev/e/vpqa8qwst4y.fsf%40anie.imag.fr In-Reply-To: <201511012230.tA1MUGa5016836@tezro.nonet> ``` "Rainer M. Canavan" writes: > Hi, Hi, Thanks for the patch. However, it will need a bit more work to be integrated into git.git. Please, read https://github.com/git/git/blob/master/Documentation/SubmittingPatches The body of your email should end up being the commit message. It is not (yet) properly written as such. Also, read about Developer's Certificate of Origin in the document above. > for opt in "" -mt -pthread -lpthread; do > old_CFLAGS="$CFLAGS" > - CFLAGS="$opt $CFLAGS" > + old_LIBS="$LIBS" > + if test "$(echo $opt | cut -b 1-2)" = -l ; then Don't use "echo" on string that may begin with - (different versions of echo will have different behaviors). One option is to use "printf" which is more robust. Another one, more elegant IMHO in this case is to use a case: case "$opt" in -l*) # ... ;; *) # ... ;; esac -- Matthieu Moy http://www-verimag.imag.fr/~moy/ ``` ## Rainer M. Canavan, 2015-11-06 01:11 Subject: [PATCH] In configure.ac, try -lpthread in $LIBS instead of $CFLAGS to make picky linkers happy Message-ID: <201511060111.tA61BbFX084361@tezro.nonet> URL: https://gitlist.dev/e/201511060111.tA61BbFX084361%40tezro.nonet In-Reply-To: ``` Some linkers, namely the one on IRIX are rather strict concerning the order or arguments for symbol resolution, i.e. no libraries listed before objects or other libraries on the command line are considered for symbol resolution. Therefore, -lpthread can't work if it's put in CFLAGS, because it will not be considered for resolving pthread_key_create in conftest.o. Use $LIBS instead. Signed-off-by: Rainer Canavan --- configure.ac | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/configure.ac b/configure.ac index fd22d41..1f55009 100644 --- a/configure.ac +++ b/configure.ac @@ -1149,7 +1149,12 @@ elif test -z "$PTHREAD_CFLAGS"; then # would then trigger compiler warnings on every single file we compile. for opt in "" -mt -pthread -lpthread; do old_CFLAGS="$CFLAGS" - CFLAGS="$opt $CFLAGS" + old_LIBS="$LIBS" + case "$opt" in + -l*) LIBS="$opt $LIBS" ;; + *) CFLAGS="$opt $CFLAGS" ;; + esac + AC_MSG_CHECKING([for POSIX Threads with '$opt']) AC_LINK_IFELSE([PTHREADTEST_SRC], [AC_MSG_RESULT([yes]) @@ -1161,6 +1166,7 @@ elif test -z "$PTHREAD_CFLAGS"; then ], [AC_MSG_RESULT([no])]) CFLAGS="$old_CFLAGS" + LIBS="$old_LIBS" done if test $threads_found != yes; then AC_CHECK_LIB([pthread], [pthread_create], -- 2.6.2 ``` ## Matthieu Moy, 2015-11-06 08:25 Subject: Re: [PATCH] In configure.ac, try -lpthread in $LIBS instead of $CFLAGS to make picky linkers happy Message-ID: URL: https://gitlist.dev/e/vpqbnb7edqn.fsf%40anie.imag.fr In-Reply-To: <201511060111.tA61BbFX084361@tezro.nonet> ``` "Rainer M. Canavan" writes: > Subject: Re: [PATCH] In configure.ac, try -lpthread in $LIBS instead of $CFLAGS to make picky linkers happy The patch looks good, but the subject should be improved. We normally try to stick to 50 characters (to let "git log --oneline" fit in a 80 columns terminal). 50 is a bit strict and not always followed, but yours is definitely too long. Also, the convention is "subsystem: what you did". I'd suggest this: configure.ac: try -lpthread in $LIBS instead of $CFLAGS The "to make picky linkers happy" is important, but redundant with the body of the message. -- Matthieu Moy http://www-verimag.imag.fr/~moy/ ``` ## Rainer M. Canavan, 2015-11-08 15:28 Subject: [PATCH] configure.ac: try -lpthread in $LIBS instead of $CFLAGS Message-ID: <201511081528.tA8FSgdc003895@tezro.nonet> URL: https://gitlist.dev/e/201511081528.tA8FSgdc003895%40tezro.nonet In-Reply-To: ``` Some linkers, namely the one on IRIX are rather strict concerning the order or arguments for symbol resolution, i.e. no libraries listed before objects or other libraries on the command line are considered for symbol resolution. That means that -lpthread can't work if it's put in CFLAGS, because it will not be considered for resolving pthread_key_create in conftest.o. Use $LIBS instead. Signed-off-by: Rainer Canavan --- configure.ac | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/configure.ac b/configure.ac index fd22d41..1f55009 100644 --- a/configure.ac +++ b/configure.ac @@ -1149,7 +1149,12 @@ elif test -z "$PTHREAD_CFLAGS"; then # would then trigger compiler warnings on every single file we compile. for opt in "" -mt -pthread -lpthread; do old_CFLAGS="$CFLAGS" - CFLAGS="$opt $CFLAGS" + old_LIBS="$LIBS" + case "$opt" in + -l*) LIBS="$opt $LIBS" ;; + *) CFLAGS="$opt $CFLAGS" ;; + esac + AC_MSG_CHECKING([for POSIX Threads with '$opt']) AC_LINK_IFELSE([PTHREADTEST_SRC], [AC_MSG_RESULT([yes]) @@ -1161,6 +1166,7 @@ elif test -z "$PTHREAD_CFLAGS"; then ], [AC_MSG_RESULT([no])]) CFLAGS="$old_CFLAGS" + LIBS="$old_LIBS" done if test $threads_found != yes; then AC_CHECK_LIB([pthread], [pthread_create], -- 2.6.2 ``` ## Matthieu Moy, 2015-11-08 16:00 Subject: Re: [PATCH] configure.ac: try -lpthread in $LIBS instead of $CFLAGS Message-ID: URL: https://gitlist.dev/e/vpqy4e8cwhr.fsf%40anie.imag.fr In-Reply-To: <201511081528.tA8FSgdc003895@tezro.nonet> ``` "Rainer M. Canavan" writes: > configure.ac | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) Looks all right to me. Thanks for you contribution and for your patience! -- Matthieu Moy http://www-verimag.imag.fr/~moy/ ``` ## Jeff King, 2015-11-20 11:42 Subject: Re: [PATCH] configure.ac: try -lpthread in $LIBS instead of $CFLAGS Message-ID: <20151120114207.GG11198@sigill.intra.peff.net> URL: https://gitlist.dev/e/20151120114207.GG11198%40sigill.intra.peff.net In-Reply-To: ``` On Sun, Nov 08, 2015 at 05:00:00PM +0100, Matthieu Moy wrote: > "Rainer M. Canavan" writes: > > > configure.ac | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > Looks all right to me. Thanks for you contribution and for your > patience! Thanks, both. I've queued this to eventually hit "maint". -Peff ```