Indicates that an internal sanity check failed.
func assertionFailure(_ message: @autoclosure () -> String = String(), file: StaticString = #file, line: UInt = #line)
A string to print in a playground or
-Ononebuild. The default is an empty string.
The file name to print with
message. The default is the file where
The line number to print along with
message. The default is the line number where
Use this function to stop the program, without impacting the performance of shipping code, when control flow is not expected to reach the call—for example, in the
default case of a
switch where you have knowledge that one of the other cases must be satisfied. To protect code from invalid usage in Release builds, see
In playgrounds and
-Ononebuilds (the default for Xcode’s Debug configuration), stop program execution in a debuggable state after printing
-Obuilds, has no effect.
-Ouncheckedbuilds, the optimizer may assume that this function is never called. Failure to satisfy that assumption is a serious programming error.