The following compile command with clang6.0:
LDFLAGS="-L/usr/local/opt/myllvm6.0rc1/lib -fuse-ld=lld"
CPPFLAGS="-I/usr/local/opt/myllvm6.0rc1/include -I/usr/local/opt/myllvm6.0rc1/include/c++/v1/";
clang++ -fsanitize=address $LDFLAGS $CPPFLAGS -g -v main.cpp
gives:
"/usr/local/opt/myllvm6.0rc1/bin/ld64.lld" -demangle -lto_library /usr/local/opt/myllvm6.0rc1/lib/libLTO.dylib -no_deduplicate -dynamic -arch x86_64 -macosx_version_min 10.11.0 -o a.out -L/usr/local/opt/myllvm6.0rc1/lib /var/folders/14/rc46ppds1ms2kj_mvdcxlc040000gn/T/main-113675.o -lc++ /usr/local/opt/myllvm6.0rc1/lib/clang/6.0.0/lib/darwin/libclang_rt.asan_osx_dynamic.dylib -rpath #executable_path -rpath /usr/local/opt/myllvm6.0rc1/lib/clang/6.0.0/lib/darwin -lSystem /usr/local/opt/myllvm6.0rc1/lib/clang/6.0.0/lib/darwin/libclang_rt.osx.a
warning: ignoring unknown argument: -no_deduplicate
warning: -sdk_version is required when emitting min version load command. Setting sdk version to match provided min version
Unable to find library for -lto_library
clang-6.0: error: linker command failed with exit code 1 (use -v to see invocation)
I dont understand why it cant load the /usr/local/opt/myllvm6.0rc1/lib/libLTO.dylib (it exists at this location!)
Any idea?
You are using -fuse-ld=lld which is what the LLD documentation says to do and as you can see ld64.lld is being run. However, the flag -no_deduplicate is not an lld flag; it is an OSX ld flag. The ld64.lld man page is here:
https://manpages.ubuntu.com/manpages/disco/man1/ld.lld.1.html
Related
I am trying to run the http://iphonedevwiki.net/index.php/Theos/Setup tutorial but stuck on this step:
./make.sh
+ xcrun -sdk macosx g++ -mmacosx-version-min=10.4 -arch i386 -arch x86_64 -I. -I/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS11.4.sdk/usr/include/libxml2 -Ilibplist/include -Ilibplist/libcnary/include -c -std=c++11 -o out/ldid.o ldid.cpp
+ xcrun -sdk macosx g++ -mmacosx-version-min=10.4 -arch i386 -arch x86_64 -I. -I/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS11.4.sdk/usr/include/libxml2 -Ilibplist/include -Ilibplist/libcnary/include -o out/ldid out/ldid.o out/iterator.o out/list.o out/node.o out/node_iterator.o out/node_list.o out/base64.o out/bplist.o out/bytearray.o out/hashtable.o out/plist.o out/ptrarray.o out/xplist.o -x c lookup2.c -lxml2 -framework Security -lcrypto
clang: warning: libstdc++ is deprecated; move to libc++ with a minimum deployment target of OS X 10.9 [-Wdeprecated]
clang: warning: libstdc++ is deprecated; move to libc++ with a minimum deployment target of OS X 10.9 [-Wdeprecated]
ld: library not found for -lcrypto
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Could you please help?
Check if -lcrypto is installed on your system (on a Linux system, you could try calling ldconfig -p | grep libcrypto, but if you are using macOS, try to find some equivalent)
Make sure your g++ call contains proper path if this library is at some specific location that will not be searched by g++ by default.
You can read about including libraries and header files in this stack overflow topic: https://stackoverflow.com/a/6141166/4802475
I follow the instruction and the ans to setup gtest for xcode. But
it still doesn't work and i got the error below:
Ld
/Users/xiaxin/Library/Developer/Xcode/DerivedData/Calculator-cchvzojufxzxgfdevhkifabakxpl/Build/Products/Debug/Tests
normal x86_64 cd /Users/xiaxin/Documents/xCode/Calculator export
MACOSX_DEPLOYMENT_TARGET=10.10
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++
-arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk
-L/Users/xiaxin/Library/Developer/Xcode/DerivedData/Calculator-cchvzojufxzxgfdevhkifabakxpl/Build/Products/Debug
-L/usr/local/lib -F/Users/xiaxin/Library/Developer/Xcode/DerivedData/Calculator-cchvzojufxzxgfdevhkifabakxpl/Build/Products/Debug
-filelist /Users/xiaxin/Library/Developer/Xcode/DerivedData/Calculator-cchvzojufxzxgfdevhkifabakxpl/Build/Intermediates/Calculator.build/Debug/Tests.build/Objects-normal/x86_64/Tests.LinkFileList
-mmacosx-version-min=10.10 -lgtest -stdlib=libc++ -framework gtest -Xlinker -dependency_info -Xlinker /Users/xiaxin/Library/Developer/Xcode/DerivedData/Calculator-cchvzojufxzxgfdevhkifabakxpl/Build/Intermediates/Calculator.build/Debug/Tests.build/Objects-normal/x86_64/Tests_dependency_info.dat
-o /Users/xiaxin/Library/Developer/Xcode/DerivedData/Calculator-cchvzojufxzxgfdevhkifabakxpl/Build/Products/Debug/Tests
ld: framework not found gtest clang: error: linker command failed with
exit code 1 (use -v to see invocation)
You need to add the GTest library to your library path. You can accomplish this on the commandline by setting -L/path/to/gtest
I am trying to install and run a this project. It is written in C++ and R. I follow the instructions and when I type the make command, I get this error:
R CMD SHLIB src/C/util.c src/C/factor_model_util.c src/C/pagerank.c src/C/hierarchical.c src/C/factor_model_multicontext.c src/C/factor_model_util2.cpp -o lib/c_funcs.so
clang++ -dynamiclib -Wl,-headerpad_max_install_names -undefined dynamic_lookup -single_module -multiply_defined suppress -L/Library/Frameworks/R.framework/Resources/lib -L/usr/local/lib -o lib/c_funcs.so src/C/util.o src/C/factor_model_util.o src/C/pagerank.o src/C/hierarchical.o src/C/factor_model_multicontext.o src/C/factor_model_util2.o -L/Library/Frameworks/R.framework/Resources/lib -lRlapack -L/Library/Frameworks/R.framework/Resources/lib -lRblas -L/usr/local/lib/gcc/x86_64-apple-darwin13.0.0/4.8.2 -lgfortran -lquadmath -lm -Wall -F/Library/Frameworks/R.framework/.. -framework R -Wl,-framework -Wl,CoreFoundation
ld: warning: directory not found for option '-L/usr/local/lib/gcc/x86_64-apple-darwin13.0.0/4.8.2'
ld: library not found for -lgfortran
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [lib/c_funcs.so] Error 1
make: *** [c_funcs] Error 1
Here is my "clang --version" results:
Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
Target: x86_64-apple-darwin14.3.0
Thread model: posix
Does anyone know what should I do? I saw the answers about xcode projects, but here I am only trying to use make for compiling.
Thanks
I had a very similar issue, and solved it by installing the newer gfortran 4.8.2. For some reason the main page links to version 4.3.2, which causes this issue (I believe because R binaries are actually built with a newer gfortran).
I have recently installed R 3.1.3. I am using a Mac with Yosemite system and my Xcode is of version 6.2.
After I source the CPP file using sourceCpp("try.cpp"), I get the following error. My try.cpp file has
#include <RcppArmadillo.h>
#include <math.h>
The error is below in R
ld: warning: directory not found for option '-L/usr/local/lib/gcc/x86_64-apple-darwin13.0.0/4.8.2'
ld: library not found for -lquadmath
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [sourceCpp_15736.so] Error 1
clang++ -arch x86_64 -ftemplate-depth-256 -I/Library/Frameworks/R.framework/Resources/include -I/usr/local/include -I/usr/local/include/freetype2 -I/opt/X11/include -I"/Library/Frameworks/R.framework/Versions/3.1/Resources/library/Rcpp/include" -I"/Library/Frameworks/R.framework/Versions/3.1/Resources/library/RcppArmadillo/include" -fPIC -mtune=core2 -O3 -c CAR.cpp -o CAR.o
clang++ -arch x86_64 -ftemplate-depth-256 -dynamiclib -Wl,-headerpad_max_install_names -undefined dynamic_lookup -single_module - multiply_defined suppress -L/Library/Frameworks/R.framework/Resources/lib - L/usr/local/lib -o sourceCpp_15736.so CAR.o -L/Library/Frameworks/R.framework/Resources/lib -lRlapack -L/Library/Frameworks/R.framework/Resources/lib -lRblas -L/usr/local/lib/gcc/x86_64-apple-darwin13.0.0/4.8.2 -lgfortran -lquadmath -lm -F/Library/Frameworks/R.framework/.. -framework R -Wl,-framework -Wl,CoreFoundation
Error in sourceCpp("~/RA2015/Code/BYMCAR/CAR.cpp") :
Error 1 occurred building shared library.
WARNING: The tools required to build C++ code for R were not found.
Please install Command Line Tools for XCode (or equivalent).
I have installed the command line tools for Xcode, my gfortran version is 4.9.0
But when I type
gfortran --version
It has the following error:
gfortran: warning: couldn’t understand kern.osversion ‘14.1.0
When I use R 3.1.2, I did not encounter this problem before!
Any help is appreciated!
After some finding I find a solution online.
If you have same problem with me, just type
curl -O http://r.research.att.com/libs/gfortran-4.8.2-darwin13.tar.bz2
sudo tar fvxz gfortran-4.8.2-darwin13.tar.bz2 -C /
on the terminal and sourceCpp can run smoothly.
A detailed explanation can be found at [http://www.thecoatlessprofessor.com/programming/rcpp-rcpparmadillo-and-os-x-mavericks-lgfortran-and-lquadmath-error]
I've been trying to figure out why g++ cannot link a program with the armadillo library. The problem is simple:
macbook-pro:arma-xc jmlopez$ g++-4.9 inputs-arma.cpp -larmadillo
ld: library not found for -larmadillo
collect2: error: ld returned 1 exit status
Perhaps I did specify where the library should be
macbook-pro:arma-xc jmlopez$ ls -l /usr/lib/libarma*
-rwxr-xr-x 1 root wheel 37928 Aug 18 14:30 /usr/lib/libarmadillo.4.32.2.dylib
lrwxr-xr-x 1 root wheel 25 Aug 18 14:30 /usr/lib/libarmadillo.4.dylib -> libarmadillo.4.32.2.dylib
lrwxr-xr-x 1 root wheel 20 Aug 18 14:30 /usr/lib/libarmadillo.dylib -> libarmadillo.4.dylib
Let us try again
macbook-pro:arma-xc jmlopez$ g++-4.9 -L/usr/lib inputs-arma.cpp -larmadillo
ld: library not found for -larmadillo
collect2: error: ld returned 1 exit status
Ok, that did not fix it. Let us see what is going on, for this we will use the -v option which will generate some long output.
macbook-pro:arma-xc jmlopez$ g++-4.9 -L/usr/lib inputs-arma.cpp -larmadillo -v
Using built-in specs.
COLLECT_GCC=g++-4.9
COLLECT_LTO_WRAPPER=/usr/local/Cellar/gcc/4.9.1/libexec/gcc/x86_64-apple-darwin13.3.0/4.9.1/lto-wrapper
Target: x86_64-apple-darwin13.3.0
Configured with: ../configure --build=x86_64-apple-darwin13.3.0 --prefix=/usr/local/Cellar/gcc/4.9.1 --enable-languages=c,c++,objc,obj-c++,fortran --program-suffix=-4.9 --with-gmp=/usr/local/opt/gmp --with-mpfr=/usr/local/opt/mpfr --with-mpc=/usr/local/opt/libmpc --with-cloog=/usr/local/opt/cloog --with-isl=/usr/local/opt/isl --with-system-zlib --enable-version-specific-runtime-libs --enable-libstdcxx-time=yes --enable-stage1-checking --enable-checking=release --enable-lto --disable-werror --with-pkgversion='Homebrew gcc 4.9.1' --with-bugurl=https://github.com/Homebrew/homebrew/issues --enable-plugin --disable-nls --enable-multilib --with-native-system-header-dir=/usr/include --with-sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk
Thread model: posix
gcc version 4.9.1 (Homebrew gcc 4.9.1)
COLLECT_GCC_OPTIONS='-mmacosx-version-min=10.9.3' '-L/usr/lib' '-v' '-shared-libgcc' '-mtune=core2'
/usr/local/Cellar/gcc/4.9.1/libexec/gcc/x86_64-apple-darwin13.3.0/4.9.1/cc1plus -quiet -v -D__DYNAMIC__ inputs-arma.cpp -fPIC -quiet -dumpbase inputs-arma.cpp -mmacosx-version-min=10.9.3 -mtune=core2 -auxbase inputs-arma -version -o /var/folders/6x/ss29s2r51z5cv0_g1ffx0c0c0000gn/T//ccApA95Q.s
GNU C++ (Homebrew gcc 4.9.1) version 4.9.1 (x86_64-apple-darwin13.3.0)
compiled by GNU C version 4.9.1, GMP version 6.0.0, MPFR version 3.1.2-p8, MPC version 1.0.2
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/local/include"
ignoring nonexistent directory "/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/../../../../x86_64-apple-darwin13.3.0/include"
ignoring nonexistent directory "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/Library/Frameworks"
#include "..." search starts here:
#include <...> search starts here:
/Users/jmlopez/github/excentury/excentury/extern/include
/usr/include
/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/include/c++
/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/include/c++/x86_64-apple-darwin13.3.0
/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/include/c++/backward
/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/include
/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/include-fixed
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/System/Library/Frameworks
End of search list.
GNU C++ (Homebrew gcc 4.9.1) version 4.9.1 (x86_64-apple-darwin13.3.0)
compiled by GNU C version 4.9.1, GMP version 6.0.0, MPFR version 3.1.2-p8, MPC version 1.0.2
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 5a051bcf2be886a5c6eb8ba33f338693
COLLECT_GCC_OPTIONS='-mmacosx-version-min=10.9.3' '-L/usr/lib' '-v' '-shared-libgcc' '-mtune=core2'
as -arch x86_64 -force_cpusubtype_ALL -o /var/folders/6x/ss29s2r51z5cv0_g1ffx0c0c0000gn/T//cchm9rVF.o /var/folders/6x/ss29s2r51z5cv0_g1ffx0c0c0000gn/T//ccApA95Q.s
COMPILER_PATH=/usr/local/Cellar/gcc/4.9.1/libexec/gcc/x86_64-apple-darwin13.3.0/4.9.1/:/usr/local/Cellar/gcc/4.9.1/libexec/gcc/x86_64-apple-darwin13.3.0/4.9.1/:/usr/local/Cellar/gcc/4.9.1/libexec/gcc/x86_64-apple-darwin13.3.0/:/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/:/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/
LIBRARY_PATH=/usr/lib/:/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/:/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/../../../:/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib/
COLLECT_GCC_OPTIONS='-mmacosx-version-min=10.9.3' '-L/usr/lib' '-v' '-shared-libgcc' '-mtune=core2'
/usr/local/Cellar/gcc/4.9.1/libexec/gcc/x86_64-apple-darwin13.3.0/4.9.1/collect2 -dynamic -arch x86_64 -macosx_version_min 10.9.3 -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -weak_reference_mismatches non-weak -o a.out -L/usr/lib -L/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1 -L/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/../../.. -L/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib /var/folders/6x/ss29s2r51z5cv0_g1ffx0c0c0000gn/T//cchm9rVF.o -larmadillo -lstdc++ -no_compact_unwind -lSystem -lgcc_ext.10.5 -lgcc -lSystem -v
collect2 version 4.9.1
/usr/bin/ld -dynamic -arch x86_64 -macosx_version_min 10.9.3 -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -weak_reference_mismatches non-weak -o a.out -L/usr/lib -L/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1 -L/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1/../../.. -L/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib /var/folders/6x/ss29s2r51z5cv0_g1ffx0c0c0000gn/T//cchm9rVF.o -larmadillo -lstdc++ -no_compact_unwind -lSystem -lgcc_ext.10.5 -lgcc -lSystem -v
#(#)PROGRAM:ld PROJECT:ld64-236.4
configured to support archs: armv6 armv7 armv7s arm64 i386 x86_64 armv6m armv7m armv7em
Library search paths:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1
/usr/local/Cellar/gcc/4.9.1/lib
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
Framework search paths:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/System/Library/Frameworks/
ld: library not found for -larmadillo
collect2: error: ld returned 1 exit status
The important information is here:
Library search paths:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1
/usr/local/Cellar/gcc/4.9.1/lib
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
Somehow it is not looking in /usr/lib. I have tried specifying this directory by first
exporting the variable LD_LIBRARY_PATH
macbook-pro:arma-xc jmlopez$ export LD_LIBRARY_PATH=/usr/lib
macbook-pro:arma-xc jmlopez$ g++-4.9 -L/usr/lib inputs-arma.cpp -larmadillo
ld: library not found for -larmadillo
collect2: error: ld returned 1 exit status
No luck. Finally, thinking that ld might be broken I did this:
macbook-pro:arma-xc jmlopez$ ln -s /usr/lib/libarmadillo.dylib /usr/local/Cellar/gcc/4.9.1/lib/libarmadillo.dylib
macbook-pro:arma-xc jmlopez$ g++-4.9 inputs-arma.cpp -larmadillo
Now it works. I'm not sure if there is something wrong with my system but it seems that I have no way of specifying other paths for ld to look for my libraries. Instead I have to use any of the following:
Library search paths:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1
/usr/local/Cellar/gcc/4.9.1/lib
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
Is there a way to fix this? Notice that I'm using the g++ from homebrew since I thought that the one that came with xcode was broken. In any case, no luck, at least the homebrew g++ told me the paths where the library was being searched.
Update:
I decided to see if I could add another path:
g++-4.9 -L/Users/jmlopez/ -L/Users/jmlopez/Desktop -L/usr/lib inputs-arma.cpp -larmadillo -v
Now the list of paths where it searches for the libraries is:
Library search paths:
/Users/jmlopez/
/Users/jmlopez/Desktop
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
/usr/local/Cellar/gcc/4.9.1/lib/gcc/x86_64-apple-darwin13.3.0/4.9.1
/usr/local/Cellar/gcc/4.9.1/lib
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/lib
Where is /usr/lib? What is so special about this directory that ld refuses to look in this directory. It searches in my home directory and in my Desktop. I tried adding /usr/local and it adds it to the list of directories. I'm now starting to wonder about the permissions on the directories... Any ideas?
It is likely that your homebrew g++ was compiled with a custom prefix. The prefix for gcc is usually /usr, meaning that it will look for binaries in /usr/bin, headers in /usr/include and libraries in /usr/lib. If you've compiled with a custom prefix (/usr/local/Cellar/gcc/4.9.1/ in this case, it seems) the it won't look in /usr/lib.
LD_LIBRARY_PATH is how you tell the runtime linker where to look for libraries. So if you had linked to /usr/my/bizarre/lib/path/libmylib.so, then you run it like this:
> LD_LIBRARY_PATH=/usr/my/bizarre/lib/path myprog
To tell g++ where to find libraries, you use the -L command-line option. So your command-line should look like this:
g++-4.9 inputs-arma.cpp -L/usr/lib -larmadillo
I ran into this thread trying to answer a similar question myself. Hopefully this will help out.
You need ld_library_path for the homebrew compiler to work and dyld_library_path for os x to appropriately use the library.
put the following exports somewhere where they can get sourced.
export LD_LIBRARY_PATH=/usr/lib:$LD_LIBRARY_PATH
export DYLD_LIBRARY_PATH=$LD_LIBRARY_PATH:$DYLD_LIBRARY_PATH
This worked for me when compiling with homebrew gcc on OS X 10.9 and 10.10.
The reason for this is that Xcode sets the SDK (in your case the macOS SDK) as the virtual root. So all search paths of the compiler and the linker are being interpreted as relative to the SDK folder.
Specifically, the Linker will not look in /usr/lib, it will look in [macOS SDK]/usr/lib.
If you need to use /usr/lib (e.g. when linking against OpenSSL's libssl which only exist in /usr/lib but not in [macOS SDK]/usr/lib, you can set "-isysroot /" as the first two "Other Linker Flags" of your project's or target's build settings. This ensures that the Linker will use / as the root (and hence will find libraries in /usr/lib), while the compiler will continue to use the virtual root set by Xcode (i.e. the macOS SDK).