Does the call to the sync function stop the execution thread?

Calling a synchronous function (sync) in iOS (for example, in Swift or Objective-C) blocks the current thread until the function completes. That is, the thread from which such a function is called is paused and will not continue executing the next code until the function returns a result.

For example, if a synchronous network request is called on the main thread, the application's interface will freeze until a response is received, which negatively impacts the user experience.

Therefore, for long operations, it is recommended to use asynchronous calls or perform synchronous operations in a background thread.