Getting an unexpected compiler flag

mzimmers

hi, all -

I recently began experimentation with building the MySQL driver plugin. One leftover problem from that effort is that, somehow I'm getting a compiler flag that I don't want, and makes building impossible.

The flag is "-std=c++1z". My version (4.9.2) of the compiler doesn't support it. I have absolutely no idea where this flag is coming from. I'm building from the command line instead of the .pro file (I have a different issue with trying to use Creator; I'll start a thread on that later if necessary.)

Here's my mysql.pro file:

TARGET = qsqlmysql

HEADERS += $$PWD/qsql_mysql_p.h
SOURCES += $$PWD/qsql_mysql.cpp $$PWD/main.cpp

QMAKE_USE += mysql

OTHER_FILES += mysql.json

PLUGIN_CLASS_NAME = QMYSQLDriverPlugin
include(../qsqldriverbase.pri)

I'm really at a loss on this one. Can anyone proffer a suggestion?

Thank you.

mrjj

@mzimmers said in Getting an unexpected compiler flag:

-std=c++1z"

Ehh is that not >2014 c++ ?
How can you get that flag with gcc 4.9 ??

Did you check qsqldriverbase.pri ?

mzimmers

Yes, that flag demands the very latest version of the compiler. I asked about updating my compiler, and was told that could be a bad idea.

Here's the contents of the .pri file:

QT  = core core-private sql-private

PLUGIN_TYPE = sqldrivers
load(qt_plugin)

DEFINES += QT_NO_CAST_TO_ASCII QT_NO_CAST_FROM_ASCII

I don't know what that load(qt_plugin) does, but I don't think that's where this flag is being generated.

mrjj

@mzimmers

Hmm nothing funky there.
If you are on linux, why not try to grep for -std=c++1z in all files ?
grep --include=*.{c,h} -rnw '/path/to/somewhere/' -e "pattern"
or
grep -Ril "text-to-find-here" /

It must be there. also strace can show files it loads ( if via system)?

It must be there somewhere :)

mzimmers

@mrjj this is all I found:

mzimmers@debian:~/QtStuff/qtbase/src/plugins/sqldrivers/mysql$ sudo grep --include=*.{c,h} -rnw '/' -e "-std=c++1z"
[sudo] password for mzimmers: 
/opt/arm-toolchain/gcc-linaro-6.2.1-2016.11-x86_64_arm-linux-gnueabihf/lib/gcc/arm-linux-gnueabihf/6.2.1/plugin/include/options.h:6509:  OPT_std_c__1z = 1294,                      /* -std=c++1z */
mzimmers@debian:~/QtStuff/qtbase/src/plugins/sqldrivers/mysql$ sudo grep --include=*.{c,h} -rnw '/' -e "OPT_std_c__1z"
/opt/arm-toolchain/gcc-linaro-6.2.1-2016.11-x86_64_arm-linux-gnueabihf/lib/gcc/arm-linux-gnueabihf/6.2.1/plugin/include/options.h:6509:  OPT_std_c__1z = 1294,                      /* -std=c++1z */
mzimmers@debian:~/QtStuff/qtbase/src/plugins/sqldrivers/mysql$

The line that the first search found is in an area I only use for cross development. I ran the second search for OPT_std_c__1z just to see if that showed up anywhere, but as you can see, nothing additional was found. Your 2nd grep command didn't work:

mzimmers@debian:~/QtStuff/qtbase/src/plugins/sqldrivers/mysql$ grep -Ril "-std=c++1z" /
grep: invalid option -- 't'
Usage: grep [OPTION]... PATTERN [FILE]...
Try 'grep --help' for more information.
mzimmers@debian:~/QtStuff/qtbase/src/plugins/sqldrivers/mysql$

I'm not sure how strace would be used to help with this...

mrjj

@mzimmers
oh sorry. didn't have lin box to test on :)

Hmm so your cross compiler is 6.2?

Just to be clear. The 4.9 u are using is not for cross compile and for some reason
it gets the flag?

mzimmers

I'm using 4.9.2 for everything now. That directory is leftover (somehow didn't get removed when I uninstalled 6.2.1) and I should probably get rid of it, but I don't think that's causing this problem.

I ran this grep (note the added files searched):

mzimmers@debian:~/QtStuff/qtbase/src/plugins/sqldrivers/mysql$ sudo grep --include=*.{c,cpp,h,conf} -rnw '/' -e "QMAKE_CXXFLAGS_CXX1Z"
/home/mzimmers/QtStuff/qtbase/mkspecs/linux-icc/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/home/mzimmers/QtStuff/qtbase/mkspecs/macx-icc/qmake.conf:57:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/home/mzimmers/QtStuff/qtbase/mkspecs/win32-g++/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/home/mzimmers/QtStuff/qtbase/mkspecs/win32-icc/qmake.conf:61:#QMAKE_CXXFLAGS_CXX1Z    = -Qstd=c++1z
/home/mzimmers/QtStuff/qtbase/mkspecs/common/clang.conf:31:QMAKE_CXXFLAGS_CXX1Z             = -std=c++1z
/home/mzimmers/QtStuff/qtbase/mkspecs/common/android-base-tail.conf:41:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/home/mzimmers/QtStuff/qtbase/mkspecs/common/g++-base.conf:32:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/home/mzimmers/QtStuff/qtbase/mkspecs/common/qcc-base-qnx.conf:47:QMAKE_CXXFLAGS_CXX1Z    = -Wc,-std=gnu++1z
/opt/Qt/5.8/src/qtbase/mkspecs/linux-icc/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/src/qtbase/mkspecs/macx-icc/qmake.conf:57:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/src/qtbase/mkspecs/win32-g++/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/src/qtbase/mkspecs/win32-icc/qmake.conf:61:#QMAKE_CXXFLAGS_CXX1Z    = -Qstd=c++1z
/opt/Qt/5.8/src/qtbase/mkspecs/common/clang.conf:31:QMAKE_CXXFLAGS_CXX1Z             = -std=c++1z
/opt/Qt/5.8/src/qtbase/mkspecs/common/android-base-tail.conf:41:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/src/qtbase/mkspecs/common/g++-base.conf:32:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/src/qtbase/mkspecs/common/qcc-base-qnx.conf:47:QMAKE_CXXFLAGS_CXX1Z    = -Wc,-std=gnu++1z
/opt/Qt/5.8/Src/qtbase/mkspecs/linux-icc/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/Src/qtbase/mkspecs/macx-icc/qmake.conf:57:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/Src/qtbase/mkspecs/win32-g++/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/Src/qtbase/mkspecs/win32-icc/qmake.conf:61:#QMAKE_CXXFLAGS_CXX1Z    = -Qstd=c++1z
/opt/Qt/5.8/Src/qtbase/mkspecs/common/clang.conf:31:QMAKE_CXXFLAGS_CXX1Z             = -std=c++1z
/opt/Qt/5.8/Src/qtbase/mkspecs/common/android-base-tail.conf:41:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/Src/qtbase/mkspecs/common/g++-base.conf:32:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/Src/qtbase/mkspecs/common/qcc-base-qnx.conf:47:QMAKE_CXXFLAGS_CXX1Z    = -Wc,-std=gnu++1z
/opt/Qt/5.8/gcc_64/mkspecs/linux-icc/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/gcc_64/mkspecs/macx-icc/qmake.conf:57:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/gcc_64/mkspecs/win32-g++/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/gcc_64/mkspecs/win32-icc/qmake.conf:61:#QMAKE_CXXFLAGS_CXX1Z    = -Qstd=c++1z
/opt/Qt/5.8/gcc_64/mkspecs/common/clang.conf:31:QMAKE_CXXFLAGS_CXX1Z             = -std=c++1z
/opt/Qt/5.8/gcc_64/mkspecs/common/android-base-tail.conf:41:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/gcc_64/mkspecs/common/g++-base.conf:32:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/Qt/5.8/gcc_64/mkspecs/common/qcc-base-qnx.conf:47:QMAKE_CXXFLAGS_CXX1Z    = -Wc,-std=gnu++1z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/linux-icc/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/macx-icc/qmake.conf:57:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/win32-g++/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/win32-icc/qmake.conf:61:#QMAKE_CXXFLAGS_CXX1Z    = -Qstd=c++1z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/common/clang.conf:31:QMAKE_CXXFLAGS_CXX1Z             = -std=c++1z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/common/android-base-tail.conf:41:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/common/g++-base.conf:32:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/common/qcc-base-qnx.conf:47:QMAKE_CXXFLAGS_CXX1Z    = -Wc,-std=gnu++1z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/linux-icc/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/macx-icc/qmake.conf:57:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/win32-g++/qmake.conf:63:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/win32-icc/qmake.conf:61:#QMAKE_CXXFLAGS_CXX1Z    = -Qstd=c++1z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/common/clang.conf:31:QMAKE_CXXFLAGS_CXX1Z             = -std=c++1z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/common/android-base-tail.conf:41:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/common/g++-base.conf:32:QMAKE_CXXFLAGS_CXX1Z    = -std=c++1z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/common/qcc-base-qnx.conf:47:QMAKE_CXXFLAGS_CXX1Z    = -Wc,-std=gnu++1z

Nothing here looks particularly interesting. Can you think of any other file types that might sneak in a compiler flag?

mrjj

@mzimmers

Hi
Its a bit odd where it comes from since you do it by shell.

I was wondering. Did you compile Qt (arm) with much newer compiler and then
later went back to the 4.9 one but Qt is still compiled with the other?

mrjj

Hi
Can you please look here
http://lists.qt-project.org/pipermail/interest/2016-September/024454.html

seems you can call qmake with -d to see where stuff comes from.
Maybe we can use that :)

mzimmers

Hi, mrjj -

I honestly don't remember what I used to build Qt for my ARM, but I think I built it with 4.9.2. I really don't think the ARM toolchain is what's causing this problem, though.
the -d option on qmake creates a tremendous amount of output...way too much to post here. I tried redirecting to a file using "> debug.out" at the end, but that didn't work. (I'm still new to the shell interface.)

EDIT: I looked through the output and found instances of that compiler flag in various .prf files:

sudo grep --include=*.{,prf} -rnw '/' -e "QMAKE_CXXFLAGS_CXX1Z"
[sudo] password for mzimmers: 
mzimmers@debian:~/QtStuff/qtbase/src/plugins/sqldrivers/mysql$ sudo grep --include=*.{,prf} -rnw '/' -e "1z"
/home/mzimmers/QtStuff/qtbase/mkspecs/features/default_post.prf:98:c++11|c++14|c++1z {
/home/mzimmers/QtStuff/qtbase/mkspecs/features/default_post.prf:101:        c++1z:       cxxstd = CXX1Z
/home/mzimmers/QtStuff/qtbase/mkspecs/features/qt_common.prf:17:qtConfig(c++1z): CONFIG += c++1z
/opt/Qt/5.8/src/qtbase/mkspecs/features/default_post.prf:98:c++11|c++14|c++1z {
/opt/Qt/5.8/src/qtbase/mkspecs/features/default_post.prf:101:        c++1z:       cxxstd = CXX1Z
/opt/Qt/5.8/src/qtbase/mkspecs/features/qt_common.prf:17:qtConfig(c++1z): CONFIG += c++1z
/opt/Qt/5.8/Src/qtbase/mkspecs/features/default_post.prf:98:c++11|c++14|c++1z {
/opt/Qt/5.8/Src/qtbase/mkspecs/features/default_post.prf:101:        c++1z:       cxxstd = CXX1Z
/opt/Qt/5.8/Src/qtbase/mkspecs/features/qt_common.prf:17:qtConfig(c++1z): CONFIG += c++1z
/opt/Qt/5.8/gcc_64/mkspecs/features/default_post.prf:98:c++11|c++14|c++1z {
/opt/Qt/5.8/gcc_64/mkspecs/features/default_post.prf:101:        c++1z:       cxxstd = CXX1Z
/opt/Qt/5.8/gcc_64/mkspecs/features/qt_common.prf:17:qtConfig(c++1z): CONFIG += c++1z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/features/default_post.prf:98:c++11|c++14|c++1z {
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/features/default_post.prf:101:        c++1z:       cxxstd = CXX1Z
/opt/arm-toolchain/sysroot-glibc-linaro-2.23-2016.11-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/features/qt_common.prf:17:qtConfig(c++1z): CONFIG += c++1z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/features/default_post.prf:98:c++11|c++14|c++1z {
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/features/default_post.prf:101:        c++1z:       cxxstd = CXX1Z
/opt/arm-toolchain/sysroot-eglibc-linaro-2017.01-arm-linux-gnueabihf/home/mzimmers/QtForBBB/mkspecs/features/qt_common.prf:17:qtConfig(c++1z): CONFIG += c++1z
mzimmers@debian:~/QtStuff/qtbase/src/plugins/sqldrivers/mysql$

I don't know much at all about these .prf files, but lines like this make me wonder:

qtConfig(c++1z): CONFIG += c++1z