Xcode error - Undefined symbols for architecture x

问题:

I have this error in XCode:

Undefined symbols for architecture x86_64:
"Parser::Parser(char const*)", referenced from:
  ___cxx_global_var_init in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

回答1:

Very common reason is using a static library that is compiled for 32 bit only.