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Preface armclang Command-line Options Support level definitions Summary of armclang command-line options -C -c -D -E -e -fbare-metal-pie -fbracket-depth=N -fcommon, -fno-common -fdata-sections, -fno-data-sections -ffast-math, -fno-fast-math -ffixed-rN -ffp-mode -ffunction-sections, -fno-function-sections -fident, -fno-ident @file -fldm-stm, -fno-ldm-stm -fno-builtin -fno-inline-functions -flto, -fno-lto -fexceptions, -fno-exceptions -fomit-frame-pointer, -fno-omit-frame-pointer -fropi, -fno-ropi -fropi-lowering, -fno-ropi-lowering -frwpi, -fno-rwpi -frwpi-lowering, -fno-rwpi-lowering -fshort-enums, -fno-short-enums -fshort-wchar, -fno-short-wchar -fstack-protector, -fstack-protector-all, -fstack- -fstrict-aliasing, -fno-strict-aliasing -ftrapv -fvectorize, -fno-vectorize -fvisibility -fwrapv -g, -gdwarf-2, -gdwarf-3, -gdwarf-4 -I -include -L -l -M, -MM -MD, -MMD -MF -MG -MP -MT -march -marm -masm -mbig-endian -mbranch-protection -mcmse -mcpu -mexecute-only -mfloat-abi -mfpu -mimplicit-it -mlittle-endian -mmemtag-stack, -mno-memtag-stack -mno-neg-immediates -moutline, -mno-outline -mpixolib -munaligned-access, -mno-unaligned-access -mthumb -nostdlib -nostdlibinc -o -O -pedantic -pedantic-errors -Rpass -S -save-temps -std --target -U -u -v --version --version_number --vsn -W -Wl -Xlinker -x -### Compiler-specific Keywords and Operators Compiler-specific Function, Variable, and Type Att Compiler-specific Intrinsics Compiler-specific Pragmas Other Compiler-specific Features Standard C Implementation Definition Standard C++ Implementation Definition armclang Integrated Assembler armclang Inline Assembler

-fcommon, -fno-common

1.10 -fcommon, -fno-common

Generates common zero-initialized values for tentative definitions.

Tentative definitions are declarations of variables with no storage class and no initializer.

The -fcommon option places the tentative definitions in a common block. This common definition is not associated with any particular section or object, so multiple definitions resolve to a single symbol definition at link time.

The -fno-common option generates individual zero-initialized definitions for tentative definitions. These zero-initialized definitions are placed in a ZI section in the generated object. Multiple definitions of the same symbol in different files can cause a L6200E: Symbol multiply defined linker error, because the individual definitions conflict with each other.

Default

The default is -fno-common.

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