Lock screen by API in macOS

Question

Is there an API, that can lock the screen as the menu bar entry you can add from Keychain preferences?

This Keychain function is (was) lock

Answer 1

To lock computer and show password promt for recent user you can use this code:

- (void)lockScreen
{
    MDSendAppleEventToSystemProcess(kAESleep);
}

OSStatus MDSendAppleEventToSystemProcess(AEEventID eventToSendID)
{
    AEAddressDesc                    targetDesc;
    static const ProcessSerialNumber kPSNOfSystemProcess = {0, kSystemProcess};
    AppleEvent                       eventReply          = {typeNull, NULL};
    AppleEvent                       eventToSend         = {typeNull, NULL};

    OSStatus status = AECreateDesc(typeProcessSerialNumber,
            &kPSNOfSystemProcess, sizeof(kPSNOfSystemProcess), &targetDesc);

    if ( status != noErr ) return status;

    status = AECreateAppleEvent(kCoreEventClass, eventToSendID,
            &targetDesc, kAutoGenerateReturnID, kAnyTransactionID, &eventToSend);

    AEDisposeDesc(&targetDesc);

    if ( status != noErr ) return status;

    status = AESendMessage(&eventToSend, &eventReply,
            kAENormalPriority, kAEDefaultTimeout);

    AEDisposeDesc(&eventToSend);
    if ( status != noErr ) return status;
    AEDisposeDesc(&eventReply);
    return status;
}