default_launcher.h: incorrect declaration of environ for macOS

[barracuda156]

Could we please fix this as well?

process/include/boost/process/v2/posix/default_launcher.hpp

Lines 34 to 36 in a2d2753

	#if defined(__APPLE__) || defined(__MACH__) || defined(__FreeBSD__) || defined(__DragonFly__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__sun)
	extern "C" { extern char **environ; }
	#endif

macOS should use a different declaration for environ. Usually the correct code looks like this:

#ifdef __APPLE__
#include <crt_externs.h>
#define environ (*_NSGetEnviron())
#else
extern char **environ;
#endif

[klemens-morgenstern]

Is this correct 100% of the time? Or should I just skip the forward decl and include the appropriate header?

[barracuda156]

Thank you for responding. If you mean for macOS, then

#include <crt_externs.h>
#define environ (*_NSGetEnviron())

works for all versions, as of now at least. (While generic declaration works for some versions of macOS, but not for all.)

[barracuda156]

@klemens-morgenstern Turned out, it needs a fix, since linking fails otherwise:

:info:build darwin.compile.c++ bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/pid.o
:info:build     "/opt/local/bin/g++-mp-14"   -fvisibility-inlines-hidden -Os -std=gnu++17 -D_GLIBCXX_USE_CXX11_ABI=0 -arch ppc  -fPIC -m32 -O3 -Wall -fvisibility=hidden -dynamic -gdwarf-2 -fexceptions -Wno-inline  -DBOOST_ALL_NO_LIB=1 -DBOOST_ASIO_NO_DEPRECATED -DBOOST_ATOMIC_DYN_LINK=1 -DBOOST_ATOMIC_NO_LIB=1 -DBOOST_COBALT_USE_STD_PMR=1 -DBOOST_CONTEXT_DYN_LINK=1 -DBOOST_CONTEXT_NO_LIB=1 -DBOOST_DATE_TIME_DYN_LINK=1 -DBOOST_DISABLE_ASSERTS -DBOOST_FILESYSTEM_DYN_LINK=1 -DBOOST_FILESYSTEM_NO_LIB=1 -DBOOST_PROCESS_DYN_LINK=1 -DBOOST_PROCESS_SOURCE=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_LIB=1 -DDATE_TIME_INLINE -DNDEBUG   -I"." -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/asio/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/assert/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/atomic/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/container_hash/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/context/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/core/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/describe/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/detail/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/filesystem/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/function_types/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/iterator/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/move/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/mp11/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/optional/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/predef/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/process/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/scope/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/smart_ptr/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/system/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/throw_exception/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/type_index/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/variant2/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/winapi/include"  -c -o "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/pid.o" "/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/process/src/pid.cpp"
:info:build darwin.compile.c++ bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/environment.o
:info:build     "/opt/local/bin/g++-mp-14"   -fvisibility-inlines-hidden -Os -std=gnu++17 -D_GLIBCXX_USE_CXX11_ABI=0 -arch ppc  -fPIC -m32 -O3 -Wall -fvisibility=hidden -dynamic -gdwarf-2 -fexceptions -Wno-inline  -DBOOST_ALL_NO_LIB=1 -DBOOST_ASIO_NO_DEPRECATED -DBOOST_ATOMIC_DYN_LINK=1 -DBOOST_ATOMIC_NO_LIB=1 -DBOOST_COBALT_USE_STD_PMR=1 -DBOOST_CONTEXT_DYN_LINK=1 -DBOOST_CONTEXT_NO_LIB=1 -DBOOST_DATE_TIME_DYN_LINK=1 -DBOOST_DISABLE_ASSERTS -DBOOST_FILESYSTEM_DYN_LINK=1 -DBOOST_FILESYSTEM_NO_LIB=1 -DBOOST_PROCESS_DYN_LINK=1 -DBOOST_PROCESS_SOURCE=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_LIB=1 -DDATE_TIME_INLINE -DNDEBUG   -I"." -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/asio/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/assert/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/atomic/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/container_hash/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/context/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/core/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/describe/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/detail/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/filesystem/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/function_types/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/iterator/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/move/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/mp11/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/optional/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/predef/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/process/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/scope/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/smart_ptr/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/system/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/throw_exception/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/type_index/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/variant2/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/winapi/include"  -c -o "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/environment.o" "/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/process/src/environment.cpp"
:info:build darwin.compile.c++ bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/shell.o
:info:build     "/opt/local/bin/g++-mp-14"   -fvisibility-inlines-hidden -Os -std=gnu++17 -D_GLIBCXX_USE_CXX11_ABI=0 -arch ppc  -fPIC -m32 -O3 -Wall -fvisibility=hidden -dynamic -gdwarf-2 -fexceptions -Wno-inline  -DBOOST_ALL_NO_LIB=1 -DBOOST_ASIO_NO_DEPRECATED -DBOOST_ATOMIC_DYN_LINK=1 -DBOOST_ATOMIC_NO_LIB=1 -DBOOST_COBALT_USE_STD_PMR=1 -DBOOST_CONTEXT_DYN_LINK=1 -DBOOST_CONTEXT_NO_LIB=1 -DBOOST_DATE_TIME_DYN_LINK=1 -DBOOST_DISABLE_ASSERTS -DBOOST_FILESYSTEM_DYN_LINK=1 -DBOOST_FILESYSTEM_NO_LIB=1 -DBOOST_PROCESS_DYN_LINK=1 -DBOOST_PROCESS_SOURCE=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_LIB=1 -DDATE_TIME_INLINE -DNDEBUG   -I"." -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/asio/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/assert/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/atomic/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/container_hash/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/context/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/core/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/describe/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/detail/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/filesystem/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/function_types/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/iterator/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/move/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/mp11/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/optional/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/predef/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/process/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/scope/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/smart_ptr/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/system/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/throw_exception/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/type_index/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/variant2/include" -I"/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/winapi/include"  -c -o "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/shell.o" "/opt/local/var/macports/build/_opt_local_ppcports_devel_boost187/boost187/work/boost_1_87_0/libs/process/src/shell.cpp"
:info:build darwin.link.dll bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/libboost_process-mt.dylib
:info:build     "/opt/local/bin/g++-mp-14" -dynamiclib -Wl,-single_module -install_name "/opt/local/libexec/boost/1.87/lib/libboost_process-mt.dylib"  -o "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/libboost_process-mt.dylib" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/detail/environment_posix.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/detail/environment_win.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/detail/last_error.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/detail/process_handle_windows.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/detail/throw_error.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/detail/utf8.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/ext/cmd.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/ext/cwd.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/ext/env.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/ext/exe.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/ext/proc_info.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/posix/close_handles.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/windows/default_launcher.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/environment.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/error.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/pid.o" "bin.v2/libs/process/build/darwin-14.2.0/release/power_32/boost.process.fs-boost/threading-multi/visibility-hidden/shell.o" "bin.v2/libs/date_time/build/darwin-14.2.0/release/power_32/threading-multi/visibility-hidden/libboost_date_time-mt.dylib" "bin.v2/libs/filesystem/build/darwin-14.2.0/release/power_32/threading-multi/visibility-hidden/libboost_filesystem-mt.dylib" "bin.v2/libs/system/build/darwin-14.2.0/release/power_32/threading-multi/visibility-hidden/libboost_system-mt.dylib" "bin.v2/libs/context/build/darwin-14.2.0/release/power_32/threading-multi/visibility-hidden/libboost_context-mt.dylib"      -headerpad_max_install_names -fPIC -m32 -fvisibility=hidden -fvisibility-inlines-hidden -Wl,-dead_strip -no_dead_strip_inits_and_terms -Wl,-headerpad_max_install_names -L/opt/local/lib -lMacportsLegacySupport -Wl,-rpath,/opt/local/lib/libgcc  
:info:build Undefined symbols:
:info:build   "_environ", referenced from:
:info:build       _environ$non_lazy_ptr in environment_posix.o
:info:build      (maybe you meant: __ZN5boost7process2v219process_environment8on_setupERNS1_5posix16default_launcherERKNS_10filesystem4pathEPKPKc, _environ$non_lazy_ptr )
:info:build ld: symbol(s) not found
:info:build collect2: error: ld returned 1 exit status

[barracuda156]

Empirically, what worked for me was:

1. Use the appropriate declaration:

#include <crt_externs.h>
#define environ (*_NSGetEnviron())

2. Replace ::environ with environ in two places (default_laucher.hpp, environment_posix.cpp).

With this, boost 1.87 finally compiles.