macOS Sonoma默认C++版本及升级至C++17编译libpqxx问题

问题场景 #

开发连接PostgreSQL的C++应用时，编译libpqxx库执行./configure时触发错误，核心报错为：

configure: error: This libpqxx version needs at least C++17

完整编译日志如下：

./configure
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a race-free mkdir -p... ./config/install-sh -c -d
checking for gawk... no
checking for mawk... no
checking for nawk... no
checking for awk... awk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking for g++... g++
checking whether the C++ compiler works... yes
checking for C++ compiler default output file name... a.out
checking for suffix of executables... 
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether the compiler supports GNU C++... yes
checking whether g++ accepts -g... yes
checking for g++ option to enable C++11 features... none needed
checking whether make supports the include directive... yes (GNU style)
checking dependency style of g++... gcc3
checking build system type... aarch64-apple-darwin23.2.0
checking host system type... aarch64-apple-darwin23.2.0
checking how to print strings... printf
checking for gcc... gcc
checking whether the compiler supports GNU C... yes
checking whether gcc accepts -g... yes
checking for gcc option to enable C11 features... none needed
checking whether gcc understands -c and -o together... yes
checking dependency style of gcc... gcc3
checking for a sed that does not truncate output... /usr/bin/sed
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for fgrep... /usr/bin/grep -F
checking for ld used by gcc... /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld
checking if the linker (/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld) is GNU ld... no
checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B
checking the name lister (/usr/bin/nm -B) interface... BSD nm
checking whether ln -s works... yes
checking the maximum length of command line arguments... 786432
checking how to convert aarch64-apple-darwin23.2.0 file names to aarch64-apple-darwin23.2.0 format... func_convert_file_noop
checking how to convert aarch64-apple-darwin23.2.0 file names to toolchain format... func_convert_file_noop
checking for /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld option to reload object files... -r
checking for file... file
checking for objdump... objdump
checking how to recognize dependent libraries... pass_all
checking for dlltool... no
checking how to associate runtime and link libraries... printf %s

checking for ar... ar
checking for archiver @FILE support... no
checking for strip... strip
checking for ranlib... ranlib
checking command to parse /usr/bin/nm -B output from gcc object... ok
checking for sysroot... no
checking for a working dd... /bin/dd
checking how to truncate binary pipes... /bin/dd bs=4096 count=1
checking for mt... no
checking if : is a manifest tool... no
checking for dsymutil... dsymutil
checking for nmedit... nmedit
checking for lipo... lipo
checking for otool... otool
checking for otool64... no
checking for -single_module linker flag... ld: warning: -single_module is obsolete
no
checking for -exported_symbols_list linker flag... yes
checking for -force_load linker flag... yes
checking for stdio.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for strings.h... yes
checking for sys/stat.h... yes
checking for sys/types.h... yes
checking for unistd.h... yes
checking for dlfcn.h... yes
checking for objdir... .libs
checking if gcc supports -fno-rtti -fno-exceptions... yes
checking for gcc option to produce PIC... -fno-common -DPIC
checking if gcc PIC flag -fno-common -DPIC works... yes
checking if gcc static flag -static works... no
checking if gcc supports -c -o file.o... yes
checking if gcc supports -c -o file.o... (cached) yes
checking whether the gcc linker (/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld) supports shared libraries... yes
checking dynamic linker characteristics... darwin23.2.0 dyld
checking how to hardcode library paths into programs... immediate
checking whether stripping libraries is possible... yes
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... no
checking whether to build static libraries... yes
checking how to run the C++ preprocessor... g++ -E
checking for ld used by g++... /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld
checking if the linker (/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld) is GNU ld... no
checking whether the g++ linker (/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld) supports shared libraries... yes
checking for g++ option to produce PIC... -fno-common -DPIC
checking if g++ PIC flag -fno-common -DPIC works... yes
checking if g++ static flag -static works... no
checking if g++ supports -c -o file.o... yes
checking if g++ supports -c -o file.o... (cached) yes
checking whether the g++ linker (/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld) supports shared libraries... yes
checking dynamic linker characteristics... darwin23.2.0 dyld
checking how to hardcode library paths into programs... immediate
checking whether make sets $(MAKE)... (cached) yes
checking for mkdir... /bin/mkdir
checking for doxygen... no
checking for dot... no
checking whether to enable maintainer-specific portions of Makefiles... no
checking maintainer mode... 
checking audit... 
checking suggest... 
checking for sufficient C++ language/library level... no
configure: error: This libpqxx version needs at least C++17

疑问 #

1. macOS Sonoma默认安装环境支持的C++版本是多少？
2. 能否将其升级至C++17版本？

解答 #

1. macOS Sonoma默认C++版本 #

macOS Sonoma（14.x）默认搭载的Xcode Command Line Tools或Xcode中的clang/g编译器**完全支持C17及更高版本**（如C20）。默认编译标准可能为C11或C14，但编译器本身具备C17的编译能力。可通过以下命令验证：

# 查看编译器版本
g++ --version
# 测试是否支持C++17
g++ -std=c++17 -c -x c++ /dev/null -o /dev/null && echo "C++17 已支持"

2. 解决libpqxx编译的C++版本问题 #

无需额外升级编译器，只需在执行configure时显式指定C++17标准即可：

CXXFLAGS="-std=c++17" ./configure

完整编译流程：

export CXXFLAGS="-std=c++17"
./configure
make
sudo make install

若仍有问题，确保已安装最新的Xcode Command Line Tools：

xcode-select --install

内容的提问来源于stack exchange，提问作者GiuCom