each extern (C) keyword causes ld (OS X) to add a duplicate library entry
Ernest Bruce via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Thu Feb 19 10:43:13 PST 2015
Note the last two lines of this list (i am running OS X 10.10.2
and Xcode 6.1.1):
clang -v -t cprog.c dprog.a -o cprog
Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin14.1.0
Thread model: posix
"/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang"
-cc1 -triple x86_64-apple-macosx10.10.0 -emit-obj -mrelax-all
-disable-free -disable-llvm-verifier -main-file-name cprog.c
-mrelocation-model pic -pic-level 2 -mdisable-fp-elim
-masm-verbose -munwind-tables -target-cpu core2
-target-linker-version 241.9 -v -resource-dir
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/6.0
-fdebug-compilation-dir /Users/ernest/dev/inquiries/c_and_d
-ferror-limit 19 -fmessage-length 146 -stack-protector 1
-mstackrealign -fblocks -fobjc-runtime=macosx-10.10.0
-fencode-extended-block-signature -fdiagnostics-show-option
-fcolor-diagnostics -vectorize-slp -o
/var/folders/gc/yfwyjyhn5b15xrsym2fyz6hr000327/T/cprog-897189.o
-x c cprog.c
clang -cc1 version 6.0 based upon LLVM 3.5svn default target
x86_64-apple-darwin14.1.0
ignoring nonexistent directory "/usr/local/include"
#include "..." search starts here:
#include <...> search starts here:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/6.0/include
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include
/usr/include
/System/Library/Frameworks (framework directory)
/Library/Frameworks (framework directory)
End of search list.
"/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld"
-demangle -dynamic -arch x86_64 -macosx_version_min 10.10.0 -t -o
cprog
/var/folders/gc/yfwyjyhn5b15xrsym2fyz6hr000327/T/cprog-897189.o
dprog.a -lSystem
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/6.0/lib/darwin/libclang_rt.osx.a
/var/folders/gc/yfwyjyhn5b15xrsym2fyz6hr000327/T/cprog-897189.o
/usr/lib/libSystem.dylib
/usr/lib/system/libcache.dylib
/usr/lib/system/libcommonCrypto.dylib
...
dprog.a(dprog_1_487.o)
dprog.a(dprog_2_495.o)
cprog.c includes two symbols exported from dprog.a, which uses
the extern(C) keyword on the two functions exported from dprog.a
when i remove one of the extern(C) keywords from dprog.a, ld
lists only one dprog.a(dprog_x_x.o) at the end
should ld be listing multiple instances of dprog.a when dprog.a
uses multiple extern C symbols?
i built dprog.a with dmd v2.066.1
i didnt include the listings to make this inquiry short, but i
can add them if it would help (im new here, and i dont to annoy
folks too much)
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