I think this problem ultimately stems from the fact that gcc/g++ and gfortran are not from the same people on macOS. It seems like clang is configured to build for 11.0 target, whilst gcc defaults to newest available target. And indeed if I change my compile command there is no warning:
mkdir -p build && gfortran -c -o ./build/conftest.o conftest.F90 && gcc-10 -o ./build/libconftest.dylib ./build/conftest.o -dynamiclib -undefined dynamic_lookup && rm -rf ./build Note I now call gcc-10 as the linker which is the __actual__ gcc (not clang in a trench coat). Best regards, Jacob Faibussowitsch (Jacob Fai - booss - oh - vitch) Cell: (312) 694-3391 > On Feb 15, 2021, at 11:46, Jacob Faibussowitsch <jacob....@gmail.com> wrote: > > Ok so if I pass -mmacosx-version-min=11.2 to the linker the warning > disappears... > > Best regards, > > Jacob Faibussowitsch > (Jacob Fai - booss - oh - vitch) > Cell: (312) 694-3391 > >> On Feb 15, 2021, at 11:41, Jacob Faibussowitsch <jacob....@gmail.com >> <mailto:jacob....@gmail.com>> wrote: >> >> I can reproduce the warning compiling just that simple code you listed. This >> is the compile command: >> >> mkdir -p build && gfortran -c -o ./build/conftest.o conftest.F90 && gcc -o >> ./build/libconftest.dylib ./build/conftest.o -dynamiclib -undefined >> dynamic_lookup && rm -rf ./build >> >> And error: >> ld: warning: object file (./build/conftest.o) was built for newer macOS >> version (11.2) than being linked (11.0) >> >> Note I recently uninstalled and reinstalled command line tools too, which >> does not seem to have fixed it. >> >> Best regards, >> >> Jacob Faibussowitsch >> (Jacob Fai - booss - oh - vitch) >> Cell: (312) 694-3391 >> >>> On Feb 15, 2021, at 11:30, Satish Balay <ba...@mcs.anl.gov >>> <mailto:ba...@mcs.anl.gov>> wrote: >>> >>> Here is the compile command and the warning: >>> >>>>>>>>> >>> ===== Checking linker >>> Executing: gfortran -c -o >>> /var/folders/9w/7dlszmmn6q1gd5yf3r9n79bc0000gn/T/petsc-dk9aiv7x/config.setCompilers/conftest.o >>> >>> -I/var/folders/9w/7dlszmmn6q1gd5yf3r9n79bc0000gn/T/petsc-dk9aiv7x/config.setCompilers >>> >>> /var/folders/9w/7dlszmmn6q1gd5yf3r9n79bc0000gn/T/petsc-dk9aiv7x/config.setCompilers/conftest.F90 >>> >>> Successful compile: >>> Source: >>> function foo(a) >>> real:: a,x,bar >>> common /xx/ x >>> x=a >>> foo = bar(x) >>> end >>> Executing: gcc -o >>> /var/folders/9w/7dlszmmn6q1gd5yf3r9n79bc0000gn/T/petsc-dk9aiv7x/config.setCompilers/libconftest.dylib >>> -dynamiclib -single_module -undefined dynamic_lookup -multiply_defined >>> suppress >>> /var/folders/9w/7dlszmmn6q1gd5yf3r9n79bc0000gn/T/petsc-dk9aiv7x/config.setCompilers/conftest.o >>> >>> Possible ERROR while running linker: >>> stderr: >>> ld: warning: object file >>> (/var/folders/9w/7dlszmmn6q1gd5yf3r9n79bc0000gn/T/petsc-dk9aiv7x/config.setCompilers/conftest.o) >>> was built for newer macOS version (11.2) than being linked (11.0) >>> Accepted FC PIC code without compiler flag >>> >>> ============================================================================================= >>> <<<<<< >>> >>> Its likely due to the way brew built gfortran. You can try compiling a >>> simple test code and see if you can reproduce this warning. >>> >>> There is a related issue at: >>> >>> https://github.com/spack/spack/issues/21644 >>> <https://github.com/spack/spack/issues/21644> >>> >>> Satish >>> >>> >>> On Sat, 13 Feb 2021, Jacob Faibussowitsch wrote: >>> >>>> Hello All, >>>> >>>> I’ve been getting these warnings for weeks, at first I figured it was due >>>> to gfortran brew package not being updated for Big Sur, but since it has >>>> persisted through a few gfortran brew updates I’m thinking it may be petsc >>>> related. This is on clean build on master. >>>> >>>> ld: warning: object file >>>> (master-arch-darwin-c-debug/obj/sys/classes/bag/f2003-src/fsrc/bagenum.o) >>>> was built for newer macOS version (11.2) than being linked (11.0) >>>> ld: warning: object file >>>> (master-arch-darwin-c-debug/obj/sys/f90-src/fsrc/f90_fwrap.o) was built >>>> for newer macOS version (11.2) than being linked (11.0) >>>> ld: warning: object file >>>> (master-arch-darwin-c-debug/obj/sys/objects/f2003-src/fsrc/optionenum.o) >>>> was built for newer macOS version (11.2) than being linked (11.0) >>>> ld: warning: object file >>>> (master-arch-darwin-c-debug/obj/sys/fsrc/somefort.o) was built for newer >>>> macOS version (11.2) than being linked (11.0) >>>> ld: warning: object file >>>> (master-arch-darwin-c-debug/obj/sys/f90-mod/petscsysmod.o) was built for >>>> newer macOS version (11.2) than being linked (11.0) >>>> >>>> Best regards, >>>> >>>> Jacob Faibussowitsch >>>> (Jacob Fai - booss - oh - vitch) >>>> Cell: (312) 694-3391 >>>> >> >
