Debugging linker error with Xcode - sdl static library - xcode

Question

I am trying to follow this guide here for building SDL2 for iOS:
http://lazyfoo.net/tutorials/SDL/52_hello_mobile/ios_mac/index.php
I am able to build the libSDL2.a static library, however I am getting a linker error when I attempt to build his example hello world application which uses it.
Ld /Users/testuser/Library/Developer/Xcode/DerivedData/___PROJECTNAME___-egvszvnfjpicgqdtaazpczjuebut/Build/Products/Debug-iphonesimulator/___PROJECTNAME___.app/___PROJECTNAME___ normal x86_64
cd "/Users/testuser/Documents/iosBuild/SDL iOS Application"
export IPHONEOS_DEPLOYMENT_TARGET=10.0
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator10.0.sdk -L/Users/testuser/Library/Developer/Xcode/DerivedData/___PROJECTNAME___-egvszvnfjpicgqdtaazpczjuebut/Build/Products/Debug-iphonesimulator -F/Users/testuser/Library/Developer/Xcode/DerivedData/___PROJECTNAME___-egvszvnfjpicgqdtaazpczjuebut/Build/Products/Debug-iphonesimulator -filelist /Users/testuser/Library/Developer/Xcode/DerivedData/___PROJECTNAME___-egvszvnfjpicgqdtaazpczjuebut/Build/Intermediates/___PROJECTNAME___.build/Debug-iphonesimulator/___PROJECTNAME___.build/Objects-normal/x86_64/___PROJECTNAME___.LinkFileList -mios-simulator-version-min=10.0 -Xlinker -object_path_lto -Xlinker /Users/testuser/Library/Developer/Xcode/DerivedData/___PROJECTNAME___-egvszvnfjpicgqdtaazpczjuebut/Build/Intermediates/___PROJECTNAME___.build/Debug-iphonesimulator/___PROJECTNAME___.build/Objects-normal/x86_64/___PROJECTNAME____lto.o -Xlinker -export_dynamic -Xlinker -no_deduplicate -Xlinker -objc_abi_version -Xlinker 2 -lSDL2 -framework GameController -framework Foundation -framework UIKit -framework OpenGLES -framework QuartzCore -framework CoreAudio -framework AudioToolbox -framework CoreGraphics -framework CoreMotion -Xlinker -dependency_info -Xlinker /Users/testuser/Library/Developer/Xcode/DerivedData/___PROJECTNAME___-egvszvnfjpicgqdtaazpczjuebut/Build/Intermediates/___PROJECTNAME___.build/Debug-iphonesimulator/___PROJECTNAME___.build/Objects-normal/x86_64/___PROJECTNAME____dependency_info.dat -o /Users/testuser/Library/Developer/Xcode/DerivedData/___PROJECTNAME___-egvszvnfjpicgqdtaazpczjuebut/Build/Products/Debug-iphonesimulator/___PROJECTNAME___.app/___PROJECTNAME___
ld: library not found for -lSDL2
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Per his instructions, I copied the project template and added the libSDL2.a lib that I built under the Build Phases -> link binary with libraries menu:
Any suggestions for how I can debug this problem?
Edit: My build target configuration in the project which uses the library:

Answer 1

try to build your library with this script. the final product will be placed in your home ~/SDL directory.
#!/bin/sh
PREFIX=$HOME/SDL
SYMROOT="SYMROOT=$PREFIX/release"
SDK_DEVICE="-sdk iphoneos"
SDK_SIMULATOR="-sdk iphonesimulator"
CONF_DEBUG="-configuration Debug"
CONF_RELEASE="-configuration Release"
mkdir -p $PREFIX
cd $PREFIX
wget https://www.libsdl.org/release/SDL2-2.0.4.zip
unzip SDL2-2.0.4.zip
rm -f SDL2-2.0.4.zip
# ------------------------------------------------------------------------
# SDL
# ------------------------------------------------------------------------
cd $PREFIX/SDL2-2.0.4/Xcode-iOS/SDL
SCHEME="libSDL"
PROJ="-project SDL.xcodeproj"
#xcodebuild OTHER_CFLAGS="-fembed-bitcode" OTHER_LDFLAGS="-lobjc" ONLY_ACTIVE_ARCH=NO -arch i386 -arch x86_64 $PROJ $SDK_SIMULATOR $CONF_DEBUG -scheme='$SCHEME' build $SYMROOT
xcodebuild OTHER_CFLAGS="-fembed-bitcode" ONLY_ACTIVE_ARCH=NO -arch i386 -arch x86_64 $PROJ $SDK_SIMULATOR $CONF_RELEASE -scheme='$SCHEME' build $SYMROOT
#xcodebuild OTHER_CFLAGS="-fembed-bitcode" OTHER_LDFLAGS="-lobjc" ONLY_ACTIVE_ARCH=NO -arch arm64 -arch armv7 $PROJ $SDK_DEVICE $CONF_DEBUG -scheme='$SCHEME' build $SYMROOT
xcodebuild OTHER_CFLAGS="-fembed-bitcode" ONLY_ACTIVE_ARCH=NO -arch arm64 -arch armv7 $PROJ $SDK_DEVICE $CONF_RELEASE -scheme='$SCHEME' build $SYMROOT
lipo $PREFIX/release/Release-iphonesimulator/libSDL2.a $PREFIX/release/Release-iphoneos/libSDL2.a -create -output $PREFIX/libSDL2.a

Answer 2

It's likely that the static library you built does not contain the architecture for which you're building your application. You'll need to build a static library that contains the architectures for the platform you want to build.
Also, keep in mind that it's not actually supported to put architectures for different platforms (such as iOS and tvOS, or even iOS and iOS Simulator—the simulators are separate platforms) in a single binary. You'll need a separate library or framework for each platform you're targeting, though each one can of course contain slices for all of that platform's supported architectures.