Enumerated Types • 17. Structures • 18. Command line parameters • 19. Header files • 20. The preprocessor ☐ 20.1. Conditionals 20.2. Symbolic constants o 20.3. Macros 20.4. If defined ☐ 20.5. Predefined functions, and you had to type: #include to use it. #include is a preprocessor directive. The preprocessor goes and looks up the stdio.h file in the standard library, because you used brackets a Makefile is necessary to tell the compiler how to compile the program. ### 20. The preprocessor The preprocessor is a tool that helps us a lot when programming with C. It is part of the C Standard,

state — File: a.hpp class A { private: char const* u_cant_touch_this() { return "Preprocessor hits me so hard"; } }; — File: main.cpp #define private public #include #undef scanning has unknown performance characteristics at scale • A human trying to understand the preprocessor state will have to do the same emulation the compiler does (Raise your hand if you want to teach export module lib; using ::AwesomeType; ## Modularizing legacy libraries - Preprocessor macros — File: libm.cpp export module lib; #define AWESOME_MACRO 42 — File: main.cpp import lib;

version information ..... 146 13.5 Inserting an application icon ..... 146 13.6 Using a Pascal preprocessor ..... 147 A Anatomy of a unit file ..... 148 A.1 Basics ..... 148 A.2 reading ppufiles pascal source will be replaced with the value of the macro (much like the macro support in the C preprocessor). If macro support is required, the -Sm command line switch must be used to switch it on, or the Defining a macro in a program is done in the same way as defining a symbol; in a $ \ $ define preprocessor statement $ ^{1} $ : { $define ident:=expr} If the compiler encounters ident in the rest of

frameworkdns = [] # Directories where OSX frameworks can be found # Flags self.cpp_info.defines = [] # preprocessor definitions self.cpp_info.cflags = [] # pure C flags self.cpp_info.cxxflags = [] # C++ compilation package root), of directories containing OSX frameworks. ## Flags: • defines: Ordered list of preprocessor directives. It is common that the consumers have to specify some sort of defines in some cases _64.xcconfig and declares the following Xcode build settings: SYSTEM_HEADER_SEARCH_PATHS, GCC_PREPROCESSOR_DEFINITIONS, OTHER_CFLAGS, OTHER_CPLUSPLUSFLAGS, FRAMEWORK_SEARCH_PATHS, LIBRARY_SEARCH_PATHS

frameworkdns = [] # Directories where OSX frameworks can be found # Flags self.cpp_info.defines = [] # preprocessor definitions self.cpp_info.cflags = [] # pure C flags self.cpp_info.cxxflags = [] # C++ compilation package root), of directories containing OSX frameworks. ## Flags: • defines: Ordered list of preprocessor directives. It is common that the consumers have to specify some sort of defines in some cases 6_64.xconfig and declares the following Xcode build settings: SYSTEM_HEADER_SEARCH_PATHS, GCC_PREPROCESSOR_DEFINITIONS, OTHER_CFLAGS, OTHER_CPLUSPLUSFLAGS, FRAMEWORK_SEARCH_PATHS, LIBRARY_SEARCH_PATHS

frameworkdns = [] # Directories where OSX frameworks can be found # Flags self.cpp_info.defines = [] # preprocessor definitions self.cpp_info.cflags = [] # pure C flags self.cpp_info.cxxflags = [] # C++ compilation package root), of directories containing OSX frameworks. ## Flags: • defines: Ordered list of preprocessor directives. It is common that the consumers have to specify some sort of defines in some cases 6_64.xconfig and declares the following Xcode build settings: SYSTEM_HEADER_SEARCH_PATHS, GCC_PREPROCESSOR_DEFINITIONS, OTHER_CFLAGS, OTHER_CPLUSPLUSFLAGS, FRAMEWORK_SEARCH_PATHS, LIBRARY_SEARCH_PATHS

frameworkdirs = [] # Directories where OSX frameworks can be found # Flags self.cpp_info.defines = [] # preprocessor definitions self.cpp_info.cflags = [] # pure C flags (continues on next page) (continued from package root), of directories containing OSX frameworks. ## Flags: • defines: Ordered list of preprocessor directives. It is common that the consumers have to specify some sort of defines in some cases 6_64.xconfig and declares the following Xcode build settings: SYSTEM_HEADER_SEARCH_PATHS, GCC_PREPROCESSOR_DEFINITIONS, OTHER_CFLAGS, OTHER_CPLUSPLUSFLAGS, FRAMEWORK_SEARCH_PATHS, LIBRARY_SEARCH_PATHS

frameworkdns = [] # Directories where OSX frameworks can be found # Flags self.cpp_info.defines = [] # preprocessor definitions self.cpp_info.cflags = [] # pure C flags self.cpp_info.cxxflags = [] # C++ compilation package root), of directories containing OSX frameworks. ## Flags: • defines: Ordered list of preprocessor directives. It is common that the consumers have to specify some sort of defines in some cases _64.xcconfig and declares the following Xcode build settings: SYSTEM_HEADER_SEARCH_PATHS, GCC_PREPROCESSOR_DEFINITIONS, OTHER_CFLAGS, OTHER_CPLUSPLUSFLAGS, FRAMEWORK_SEARCH_PATHS, LIBRARY_SEARCH_PATHS

language preprocessor, except that the special character # has been changed to the exclamation mark !. ### 19.1 Migration notes The actual preprocessor is an update from some legacy preprocessor. Even Even if some legacy feature are still supported with the actual preprocessor, you should not use them any more (they might be finally removed in some long term future). • You should not use !define and !definelong my_own_definelong() because my_own_definelong without parenthesis is not recognized by the new preprocessor. Please contact us if you have any issues. ### 19.2 Variable definition Although this is not