What is preprocessor macros in Xcode?

Preprocessor Macros are directives executed by the compiler, so they’re not part of Objective C. We’ve used them many times before with the #import statement. But to stay with our Lite and Pro example: you can use a Preprocessor if/then statement to check which version is being compiled.

How do I use macros in Xcode?

2 Answers

  1. Select project file.
  2. Select the target you want.
  3. Go to Build Settings.
  4. Search for ‘preprocessor’
  5. Add your preprocessor macro either for Debug, Release, or both.

What is difference between preprocessor and macros?

macros are name for fragment of code. A macro processor is a program that copies a stream of text from one place to another, making a systematic set of replacements as it does so. A preprocessor is a program that processes its input data to produce output that is used as input to another program.

What is compilation conditions in Swift?

From the Xcode 8 release notes: Active Compilation Conditions is a new build setting for passing conditional compilation flags to the Swift compiler. Each element of the value of this setting passes to swiftc prefixed with -D , in the same way that elements of Preprocessor Macros pass to clang with the same prefix. (

How do I add compiler flags in Xcode?

You can then add swift compiler flags so that we can check the current configuration through code. To do that, goto Project (not target)→Build settings → Swift Compiler → Custom flags → Other swift flags section and edit the different configuration flags. Add the flags using the syntax “ -D ”.

What is preprocessor with example?

A common example from computer programming is the processing performed on source code before the next step of compilation. In some computer languages (e.g., C and PL/I) there is a phase of translation known as preprocessing. It can also include macro processing, file inclusion and language extensions.

Is it better to use a macro or a function?

Macros have the distinct advantage of being more efficient (and faster) than functions, because their corresponding code is inserted directly into your source code at the point where the macro is called. There is no overhead involved in using a macro like there is in placing a call to a function.

What are macros in Swift?

Macros in Swift programming are generally the block of code available to the developer as a single statement. A single block of code consists of a large number of statements or instructions. Hence making the development less tedious.

What is difference between if let and guard in Swift?

In if let , the defined let variables are available within the scope of that if condition but not in else condition or even below that. In guard let , the defined let variables are not available in the else condition but after that, it’s available throughout till the function ends or anything.