Apple Mach-O Linked Error - ios

Hi i all i found a lot of answer but didn't get the solution. Here i am posting my error that i am getting. Please help me get rid of this.
Ld /Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Products/Debug-iphonesimulator/JEDI.app/JEDI normal i386
cd /Applications/XAMPP/xamppfiles/htdocs/bsharp/sites/default/iOS_Development/JEDI
export IPHONEOS_DEPLOYMENT_TARGET=7.0
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.0.sdk -L/Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Products/Debug-iphonesimulator -F/Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Products/Debug-iphonesimulator -filelist /Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Intermediates/JEDI.build/Debug-iphonesimulator/JEDI.build/Objects-normal/i386/JEDI.LinkFileList -Xlinker -rpath -Xlinker #executable_path/Frameworks -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=7.0 -Xlinker -dependency_info -Xlinker /Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Intermediates/JEDI.build/Debug-iphonesimulator/JEDI.build/Objects-normal/i386/JEDI_dependency_info.dat -o /Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Products/Debug-iphonesimulator/JEDI.app/JEDI
duplicate symbol _IS_ALREADY_LOGIN in:
/Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Intermediates/JEDI.build/Debug-iphonesimulator/JEDI.build/Objects-normal/i386/CustomCell.o
/Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Intermediates/JEDI.build/Debug-iphonesimulator/JEDI.build/Objects-normal/i386/ViewController.o
duplicate symbol _TRUE_CHECK in:
/Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Intermediates/JEDI.build/Debug-iphonesimulator/JEDI.build/Objects-normal/i386/CustomCell.o
/Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Intermediates/JEDI.build/Debug-iphonesimulator/JEDI.build/Objects-normal/i386/ViewController.o
duplicate symbol _FONT_NAME in:
/Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Intermediates/JEDI.build/Debug-iphonesimulator/JEDI.build/Objects-normal/i386/CustomCell.o
/Users/Rupesh/Library/Developer/Xcode/DerivedData/JEDI-fptiyjulpownybgfqknfffphqrvl/Build/Intermediates/JEDI.build/Debug-iphonesimulator/JEDI.build/Objects-normal/i386/ViewController.o
ld: 3 duplicate symbols for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Your project contains duplicate symbols which means you're trying to compile two identical files which contain the implementation for the same class. Check your project files and eliminate any duplicate .m files (like CustomCell and ViewController)
Maybe _IS_ALREADY_LOGIN, _TRUE_CHECK etc is defined more than once in CustomCell.h/m and ViewController.h/m?

Related

1 duplicate symbol for architecture arm64 - Xcode - running out of ideas

I've had this issue for a few days now, I've tried all the stuff on Stackoverflow so far and have no where to turn to and I don't know what to do.
Error:
ld: 1 duplicate symbol for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Any suggestions?
Paste bin to entire log:
https://pastebin.pl/view/dfc1fdca
Relevant entries from the log:
Showing Recent Messages
Ld /Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Products/Debug-iphoneos/Countdown\ Widget.app/Countdown\ Widget normal (in target 'Countdown Widget' from project 'Countdown Widget')
cd /Users/bradleycable/Desktop/Stuff/Countdown\ Widget
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -target arm64-apple-ios14.0 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS14.2.sdk -L/Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Products/Debug-iphoneos -F/Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Products/Debug-iphoneos -F/Users/bradleycable/Desktop/Stuff/Countdown\ Widget -filelist /Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Intermediates.noindex/Countdown\ Widget.build/Debug-iphoneos/Countdown\ Widget.build/Objects-normal/arm64/Countdown\ Widget.LinkFileList -Xlinker -rpath -Xlinker #executable_path/Frameworks -dead_strip -Xlinker -object_path_lto -Xlinker /Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Intermediates.noindex/Countdown\ Widget.build/Debug-iphoneos/Countdown\ Widget.build/Objects-normal/arm64/Countdown\ Widget_lto.o -Xlinker -no_deduplicate -fobjc-link-runtime -L/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphoneos -L/usr/lib/swift -Xlinker -add_ast_path -Xlinker /Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Intermediates.noindex/Countdown\ Widget.build/Debug-iphoneos/Countdown\ Widget.build/Objects-normal/arm64/Countdown_Widget.swiftmodule -framework Foundation -framework UIKit -Xlinker -no_adhoc_codesign -Xlinker -dependency_info -Xlinker /Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Intermediates.noindex/Countdown\ Widget.build/Debug-iphoneos/Countdown\ Widget.build/Objects-normal/arm64/Countdown\ Widget_dependency_info.dat -o /Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Products/Debug-iphoneos/Countdown\ Widget.app/Countdown\ Widget -Xlinker -add_ast_path -Xlinker /Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Intermediates.noindex/SQLite.swift.build/Debug-iphoneos/SQLite.build/Objects-normal/arm64/SQLite.swiftmodule
duplicate symbol '_main' in:
/Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Intermediates.noindex/Countdown Widget.build/Debug-iphoneos/Countdown Widget.build/Objects-normal/arm64/Wtarget-fb79391fc42d00bcc0af801429653506c80531174bbc6c7603c27c78464dee8a.o
/Users/bradleycable/Library/Developer/Xcode/DerivedData/Countdown_Widget-hhxapyypudwfqifpmwtzlpoaerys/Build/Intermediates.noindex/Countdown Widget.build/Debug-iphoneos/Countdown Widget.build/Objects-normal/arm64/Countdown_WidgetApp.o
ld: 1 duplicate symbol for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
This is a typical error that appears during link time due to multiple files exporting the same symbols.
For this particular problem, you seem to have two files in your project that declare the main function:
Countdown_WidgetApp,
and the oddly named Wtarget-fb79391fc42d00bcc0af801429653506c80531174bbc6c7603c27c78464dee8a
Take a look at the contents of those files and either remove one from the project or remove the main declaration from one of them.

getting error linker command failed with exit code 1 when compiling app

I am new to iOS and I was working through this tutorial (scroll down to Prototype cells ), when I tried to compile my app, i got the following error below. the first part of my question is, how can I make sense of anything in there? I have no idea how to interpret it. Can you guide me on what could be the problem?
Ld /Users/nadirahmed/Library/Developer/Xcode/DerivedData/prototypeCustomCellExample-dgygyvcibtndywgeapixzpvxohkj/Build/Products/Debug-iphonesimulator/prototypeCustomCellExample.app/prototypeCustomCellExample normal x86_64
cd /Users/nadirahmed/Documents/iOS/prototypeCustomCellExample
export IPHONEOS_DEPLOYMENT_TARGET=9.0
export PATH="/Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode-beta.app/Contents/Developer/usr/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch x86_64 -isysroot /Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator9.0.sdk -L/Users/nadirahmed/Library/Developer/Xcode/DerivedData/prototypeCustomCellExample-dgygyvcibtndywgeapixzpvxohkj/Build/Products/Debug-iphonesimulator -F/Users/nadirahmed/Library/Developer/Xcode/DerivedData/prototypeCustomCellExample-dgygyvcibtndywgeapixzpvxohkj/Build/Products/Debug-iphonesimulator -filelist /Users/nadirahmed/Library/Developer/Xcode/DerivedData/prototypeCustomCellExample-dgygyvcibtndywgeapixzpvxohkj/Build/Intermediates/prototypeCustomCellExample.build/Debug-iphonesimulator/prototypeCustomCellExample.build/Objects-normal/x86_64/prototypeCustomCellExample.LinkFileList -Xlinker -rpath -Xlinker #executable_path/Frameworks -mios-simulator-version-min=9.0 -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -Xlinker -dependency_info -Xlinker /Users/nadirahmed/Library/Developer/Xcode/DerivedData/prototypeCustomCellExample-dgygyvcibtndywgeapixzpvxohkj/Build/Intermediates/prototypeCustomCellExample.build/Debug-iphonesimulator/prototypeCustomCellExample.build/Objects-normal/x86_64/prototypeCustomCellExample_dependency_info.dat -o /Users/nadirahmed/Library/Developer/Xcode/DerivedData/prototypeCustomCellExample-dgygyvcibtndywgeapixzpvxohkj/Build/Products/Debug-iphonesimulator/prototypeCustomCellExample.app/prototypeCustomCellExample
duplicate symbol __players in:
/Users/nadirahmed/Library/Developer/Xcode/DerivedData/prototypeCustomCellExample-dgygyvcibtndywgeapixzpvxohkj/Build/Intermediates/prototypeCustomCellExample.build/Debug-iphonesimulator/prototypeCustomCellExample.build/Objects-normal/x86_64/AppDelegate.o
/Users/nadirahmed/Library/Developer/Xcode/DerivedData/prototypeCustomCellExample-dgygyvcibtndywgeapixzpvxohkj/Build/Intermediates/prototypeCustomCellExample.build/Debug-iphonesimulator/prototypeCustomCellExample.build/Objects-normal/x86_64/Player.o
ld: 1 duplicate symbol for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
just check:
1.Try finding in the whole project your class Player and make sure only one copy is available within your project.
2.You could also get this error if you mistakenly let XCode's auto-complete for #import statements specify the '.m" file for the
'duplicate' class instead of the '.h'.
THANKS

clang: error: linker command failed with exit code 1 (use -v to see invocation) ID file not found

I know this question is asked several time, but unfortunately I am asking it again as I am not getting its solution. I am trying to solve this error from last few couple of days and I am unable to solve this.
Ld /Users/admin/Library/Developer/Xcode/DerivedData/QMS-cacudjkdofhyczasnkiyzjzfwjpc/Build/Products/Debug-iphonesimulator/QMSTests.xctest/QMSTests normal x86_64
cd "/Users/admin/Documents/iPhone Apps/Divya/QMS"
export IPHONEOS_DEPLOYMENT_TARGET=8.1
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch x86_64 -bundle -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.1.sdk -L/Users/admin/Library/Developer/Xcode/DerivedData/QMS-cacudjkdofhyczasnkiyzjzfwjpc/Build/Products/Debug-iphonesimulator -F/Users/admin/Library/Developer/Xcode/DerivedData/QMS-cacudjkdofhyczasnkiyzjzfwjpc/Build/Products/Debug-iphonesimulator -F/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.1.sdk/Developer/Library/Frameworks -F/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Frameworks -F/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.1.sdk/Developer/Library/Frameworks -filelist /Users/admin/Library/Developer/Xcode/DerivedData/QMS-cacudjkdofhyczasnkiyzjzfwjpc/Build/Intermediates/QMS.build/Debug-iphonesimulator/QMSTests.build/Objects-normal/x86_64/QMSTests.LinkFileList -Xlinker -rpath -Xlinker #executable_path/Frameworks -Xlinker -rpath -Xlinker #loader_path/Frameworks -bundle_loader /Users/admin/Library/Developer/Xcode/DerivedData/QMS-cacudjkdofhyczasnkiyzjzfwjpc/Build/Products/Debug-iphonesimulator/QMS.app/QMS -Xlinker -objc_abi_version -Xlinker 2 -framework XCTest -L/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator -Xlinker -add_ast_path -Xlinker /Users/admin/Library/Developer/Xcode/DerivedData/QMS-cacudjkdofhyczasnkiyzjzfwjpc/Build/Intermediates/QMS.build/Debug-iphonesimulator/QMSTests.build/Objects-normal/x86_64/QMSTests.swiftmodule -mios-simulator-version-min=8.1 -Xlinker -dependency_info -Xlinker /Users/admin/Library/Developer/Xcode/DerivedData/QMS-cacudjkdofhyczasnkiyzjzfwjpc/Build/Intermediates/QMS.build/Debug-iphonesimulator/QMSTests.build/Objects-normal/x86_64/QMSTests_dependency_info.dat -o /Users/admin/Library/Developer/Xcode/DerivedData/QMS-cacudjkdofhyczasnkiyzjzfwjpc/Build/Products/Debug-iphonesimulator/QMSTests.xctest/QMSTests
ld: file not found: /Users/admin/Library/Developer/Xcode/DerivedData/QMS-cacudjkdofhyczasnkiyzjzfwjpc/Build/Products/Debug-iphonesimulator/QMS.app/QMS
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Please help me,tell me the way how can I solve it.
Thank you in advance.
You may have moved the folder from one mac to another.
Old references are not finding the file.
The files which have not been detected, should be showing in RED Font color in project navigator (on the left side of xcode).
Try adding these file manually by just dragging the files directly to your project navigator.

Xcode - Importing STTwitter causes Apple Mach-O Linker Error

Exactly what it says on the title. I've downloaded the STTwitter API several times making sure nothing went wrong with my download. I ran my project before importing the library and it runs fine.
I know there is nothing wrong with the STTwitter library because I used it in several projects, but it won't let me create another project with the import.
Ld /Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Products/Debug-iphonesimulator/JesusWalk.app/JesusWalk normal i386
cd /Users/michaelvillar/Desktop/JesusWalk
export IPHONEOS_DEPLOYMENT_TARGET=8.3
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.3.sdk -L/Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Products/Debug-iphonesimulator -F/Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Products/Debug-iphonesimulator -filelist /Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Intermediates/JesusWalk.build/Debug-iphonesimulator/JesusWalk.build/Objects-normal/i386/JesusWalk.LinkFileList -Xlinker -rpath -Xlinker #executable_path/Frameworks -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=8.3 -framework Foundation -framework UIKit -framework CoreGraphics -Xlinker -dependency_info -Xlinker /Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Intermediates/JesusWalk.build/Debug-iphonesimulator/JesusWalk.build/Objects-normal/i386/JesusWalk_dependency_info.dat -o /Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Products/Debug-iphonesimulator/JesusWalk.app/JesusWalk
duplicate symbol _STTwitterOSErrorCode in:
/Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Intermediates/JesusWalk.build/Debug-iphonesimulator/JesusWalk.build/Objects-normal/i386/STTwitterOS.o
/Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Intermediates/JesusWalk.build/Debug-iphonesimulator/JesusWalk.build/Objects-normal/i386/STTwitterAPI.o
duplicate symbol _STTwitterAppOnlyErrorCode in:
/Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Intermediates/JesusWalk.build/Debug-iphonesimulator/JesusWalk.build/Objects-normal/i386/STTwitterAPI.o
/Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Intermediates/JesusWalk.build/Debug-iphonesimulator/JesusWalk.build/Objects-normal/i386/STTwitterAppOnly.o
duplicate symbol _STTwitterOAuthErrorCode in:
/Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Intermediates/JesusWalk.build/Debug-iphonesimulator/JesusWalk.build/Objects-normal/i386/STTwitterAPI.o
/Users/michaelvillar/Library/Developer/Xcode/DerivedData/JesusWalk-evjafkmkrrhusqauysjaelfarvqn/Build/Intermediates/JesusWalk.build/Debug-iphonesimulator/JesusWalk.build/Objects-normal/i386/STTwitterOAuth.o
ld: 3 duplicate symbols for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Please, if anyone knows something about importing the library, let me know :)
This pull request may fix the issue: https://github.com/nst/STTwitter/pull/189
Please checkout the very latest version from head.

Apple Mach O Linker Error

Hope you guys know how to fix this one. I probably just need to add a framework to the link binary but I can't really find which one to add.
Ld
/Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Products/Debug-iphonesimulator/Sum.app/Sum
normal i386
cd /Users/Chrismac/Documents/Sum
export IPHONEOS_DEPLOYMENT_TARGET=7.1
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang
-arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator7.1.sdk
-L/Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Products/Debug-iphonesimulator
-F/Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Products/Debug-iphonesimulator
-filelist /Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Intermediates/Sum.build/Debug-iphonesimulator/Sum.build/Objects-normal/i386/Sum.LinkFileList
-Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=7.1 -framework CoreGraphics -framework UIKit -framework Foundation -Xlinker -dependency_info -Xlinker /Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Intermediates/Sum.build/Debug-iphonesimulator/Sum.build/Objects-normal/i386/Sum_dependency_info.dat -o /Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Products/Debug-iphonesimulator/Sum.app/Sum
duplicate symbol _PressIt in:
/Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Intermediates/Sum.build/Debug-iphonesimulator/Sum.build/Objects-normal/i386/SecondViewController.o
/Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Intermediates/Sum.build/Debug-iphonesimulator/Sum.build/Objects-normal/i386/FirstViewController.o
duplicate symbol _push in:
/Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Intermediates/Sum.build/Debug-iphonesimulator/Sum.build/Objects-normal/i386/SecondViewController.o
/Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Intermediates/Sum.build/Debug-iphonesimulator/Sum.build/Objects-normal/i386/FirstViewController.o
duplicate symbol _savedData in:
/Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Intermediates/Sum.build/Debug-iphonesimulator/Sum.build/Objects-normal/i386/SecondViewController.o
/Users/Chrismac/Library/Developer/Xcode/DerivedData/Sum-cyzxwtuyfesisgfvermcafpbmtgv/Build/Intermediates/Sum.build/Debug-iphonesimulator/Sum.build/Objects-normal/i386/FirstViewController.o
ld: 3 duplicate symbols for architecture i386 clang: error: linker
command failed with exit code 1 (use -v to see invocation)
You aren't missing a lib but you have 2 C functions called Pressit, Push and SavedData that conflict!
The duplicated symbols are in FirstViewController & SecondViewController.
Solution:
Don't implement the same functions twice:
If they are equal, move them to a third file and include them only.
If they differ, rename them.
I guess, you might have implemented FirstViewController three times in your project.
Search for FirstViewController throughout out the project and keep only one FirstViewController for project.

Resources