C/C++

• The 4 Stages of Compilation
  • Preprocessing
  • Compilation
  • Assembly
  • Linking
• Compiling, Linking, Interpreting
• Assembly language
• Machine language
• Header files
• object file
  • compiled from source .c or .cpp
  • extension
    • dictated by the compiler
    • .o — gcc/clang
    • .obj — cl
  • file format
    • dictated by the OS
    • ELF (Executable and Linkable Format) — Linux
    • Mach-O (Mach Object Format) — macOS
    • COFF (Common Object File Format) — Windows
• static library
  • Multiple object files are archived into one library file
  • It is just container for multiple object files
  • They are merged into executable during compilation process
  • .a (Archive) — Linux/macOS
  • .lib (Library) — Windows
• dynamic (shared) libraries
  • These are compiled code containers kept separate from the final executable
  • They are loaded into memory at runtime to save disk space and RAM.
  • .so (Shared object) — Linux
    • uses ELF format
  • .dylib (Dynamic Library) — macOS
    • uses Mach-O (Mach Object) format
  • .dll (Dynamic-Link library) — Windows
    • uses PE (Portable Executable) format
• Searching for dynamic libraries for an executable
  • ldd — Linux
  • otool or llvm-otool — macOS
  • dumpbin — Windows
• Executable
  • No extension
    • Linux
      • uses ELF format
    • MacOS
      • uses Mach-O format
  • .exe — Windows
    • uses PE format