在Swift中：

import os

os_log("Some message")

在Objective-C中：

#import <os/log.h>

os_log(OS_LOG_DEFAULT, "Some message");

还有一些高级的/有组织的日志记录方式，如https://developer.apple.com/documentation/os/logging/generating_log_messages_from_your_code中所述
在Swift中

let defaultLog = Logger()
defaultLog.log("This is a default message.")
            
// Log a message to the default log and debug log level
defaultLog.debug("This is a debug message.")

// Log an error to a custom log object.
let customLog = Logger(subsystem: "com.your_company.your_subsystem", 
          category: "your_category_name")
customLog.error("An error occurred!")

在目标C中

// Log a message to the default log and debug log level
os_log_with_type(OS_LOG_DEFAULT, OS_LOG_TYPE_DEBUG, "This is a debug message.");
    
// Log an error to a custom log object.
os_log_t customLog = os_log_create("com.your_company.your_subsystem", "your_category_name");
os_log_with_type(customLog, OS_LOG_TYPE_ERROR, "An error occurred!");