How to print out the method name and line number in swift

Question

Here is an example of what I want to do:

func application(application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: NSError)
{
            


        

Answer 1

You can use #function, #file, #line

Here is the implementation of log method in swift : https://github.com/InderKumarRathore/SwiftLog

Below is the snippet

public func debugLog(object: Any, functionName: String = #function, fileName: String = #file, lineNumber: Int = #line) {
  #if DEBUG
    let className = (fileName as NSString).lastPathComponent
    print("<\(className)> \(functionName) [#\(lineNumber)]| \(object)\n")
  #endif
}

Answer 2

static func DLog(message: String, file: String = #file, function: String = #function, line: Int = #line, column: Int = #column) {
    print("\(file) : \(function) : \(line) : \(column) - \(message)")
}

Answer 3

Literal        Type     Value

#file          String   The name of the file in which it appears.
#line          Int      The line number on which it appears.
#column        Int      The column number in which it begins.
#function      String   The name of the declaration in which it appears.
#dsohandle     UnsafeMutablePointer   The dso handle.

Example

print("Function: \(#function), line: \(#line)") 

With default values in parameters you can also create a function

public func track(_ message: String, file: String = #file, function: String = #function, line: Int = #line ) { 
    print("\(message) called from \(function) \(file):\(line)") 
}

which can be used like this

track("enters app")

In Swift 2.1

 Literal        Type     Value

__FILE__       String   The name of the file in which it appears.
__LINE__       Int      The line number on which it appears.
__COLUMN__     Int      The column number in which it begins.
__FUNCTION__   String   The name of the declaration in which it appears.

for more info see the documentation

Answer 4

For swift 4 and swift 5:

func printLog(_ message: String, file: String = #file, function: String = #function, line: Int = #line) {
    #if DEVELOPMENT
        let className = file.components(separatedBy: "/").last
        print(" ❌ Error ----> File: \(className ?? ""), Function: \(function), Line: \(line), Message: \(message)")
    #endif
}

// "❌ Error ----> File: classNameViewController.swift, function: functionName(), Line: 123, Message: messageError"