$ perl -V Summary of my perl5 (revision 5 version 12 subversion 4) configuration: Platform: osname=darwin, osvers=12.0, archname=darwin-thread-multi-2level uname='darwin b1026.apple.com 12.0 darwin kernel version 12.0.0: tue may 15 23:31:29 pdt 2012; root:xnu-2050.6.70~1release_x86_64 x86_64 ' config_args='-ds -e -Dprefix=/usr -Dccflags=-g -pipe -Dldflags= -Dman3ext=3pm -Duseithreads -Duseshrplib -Dinc_version_list=none -Dcc=clang' hint=recommended, useposix=true, d_sigaction=define useithreads=define, usemultiplicity=define useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef use64bitint=define, use64bitall=define, uselongdouble=undef usemymalloc=n, bincompat5005=undef Compiler: cc='clang', ccflags =' -arch x86_64 -g -pipe -fno-common -DPERL_DARWIN -fno-strict-aliasing -fstack-protector -I/usr/local/include', optimize='-Os', cppflags='-g -pipe -fno-common -DPERL_DARWIN -fno-strict-aliasing -fstack-protector -I/usr/local/include' ccversion='', gccversion='4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)', gccosandvers='' intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678 d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16 ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8 alignbytes=8, prototype=define Linker and Libraries: ld='clang -mmacosx-version-min=10.8', ldflags =' -arch x86_64 -fstack-protector -L/usr/local/lib' libpth=/usr/local/lib /usr/lib libs=-ldbm -ldl -lm -lutil -lc perllibs=-ldl -lm -lutil -lc libc=, so=dylib, useshrplib=true, libperl=libperl.dylib gnulibc_version='' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' ' cccdlflags=' ', lddlflags=' -arch x86_64 -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector' Characteristics of this binary (from libperl): Compile-time options: MULTIPLICITY PERL_DONT_CREATE_GVSV PERL_IMPLICIT_CONTEXT PERL_MALLOC_WRAP USE_64_BIT_ALL USE_64_BIT_INT USE_ITHREADS USE_LARGE_FILES USE_PERLIO USE_PERL_ATOF USE_REENTRANT_API Locally applied patches: /Library/Perl/Updates/ comes before system perl directories installprivlib and installarchlib points to the Updates directory Built under darwin Compiled at Jun 20 2012 13:55:28 @INC: /Library/Perl/5.12/darwin-thread-multi-2level /Library/Perl/5.12 /Network/Library/Perl/5.12/darwin-thread-multi-2level /Network/Library/Perl/5.12 /Library/Perl/Updates/5.12.4/darwin-thread-multi-2level /Library/Perl/Updates/5.12.4 /System/Library/Perl/5.12/darwin-thread-multi-2level /System/Library/Perl/5.12 /System/Library/Perl/Extras/5.12/darwin-thread-multi-2level /System/Library/Perl/Extras/5.12 . $ cpanm --version cpanm (App::cpanminus) version 1.6915 (/usr/local/bin/cpanm) perl version 5.012004 (/usr/bin/perl) %Config: archname=darwin-thread-multi-2level installsitelib=/Library/Perl/5.12 installsitebin=/usr/local/bin installman1dir=/usr/share/man/man1 installman3dir=/usr/share/man/man3 sitelibexp=/Library/Perl/5.12 archlibexp=/System/Library/Perl/5.12/darwin-thread-multi-2level privlibexp=/System/Library/Perl/5.12 %ENV: @INC: /Library/Perl/5.12/darwin-thread-multi-2level /Library/Perl/5.12 /Network/Library/Perl/5.12/darwin-thread-multi-2level /Network/Library/Perl/5.12 /Library/Perl/Updates/5.12.4/darwin-thread-multi-2level /Library/Perl/Updates/5.12.4 /System/Library/Perl/5.12/darwin-thread-multi-2level /System/Library/Perl/5.12 /System/Library/Perl/Extras/5.12/darwin-thread-multi-2level /System/Library/Perl/Extras/5.12 $ clang -v Apple LLVM version 4.2 (clang-425.0.28) (based on LLVM 3.2svn) Target: x86_64-apple-darwin12.3.0 Thread model: posix $ gcc -v Using built-in specs. Target: i686-apple-darwin11 Configured with: /private/var/tmp/llvmgcc42/llvmgcc42-2336.11~182/src/configure --disable-checking --enable-werror --prefix=/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2 --mandir=/share/man --enable-languages=c,objc,c++,obj-c++ --program-prefix=llvm- --program-transform-name=/^[cg][^.-]*$/s/$/-4.2/ --with-slibdir=/usr/lib --build=i686-apple-darwin11 --enable-llvm=/private/var/tmp/llvmgcc42/llvmgcc42-2336.11~182/dst-llvmCore/Developer/usr/local --program-prefix=i686-apple-darwin11- --host=x86_64-apple-darwin11 --target=i686-apple-darwin11 --with-gxx-include-dir=/usr/include/c++/4.2.1 Thread model: posix gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)