c – OS X clang -pthread

air:~ jose$clang++ -c test.cpp -pthread
air:~ jose$clang++ -o test -pthread test.o 
clang: warning: argument unused during compilation: '-pthread'

air:~ jose$g++ -c test.cpp -pthread
air:~ jose$g++ -o test -pthread test.o

clang在编译时需要-pthread,但在链接时不需要.pthread.这很烦人,但观察到的行为：

$clang -c x.cpp
$clang -pthread -c x.cpp
$clang -o x x.o
$clang -pthread -o x x.o
clang: warning: argument unused during compilation: '-pthread'
$

$clang --version
Apple LLVM version 5.0 (clang-500.2.76) (based on LLVM 3.3svn)
Target: x86_64-apple-darwin13.0.0
Thread model: posix
$