How to find source file and line number from os_log()

问题

The Logging Apple reference for the new logging system in iOS 10 and macOS Sierra explicitly say not to include line number and source file info, because it is automatically captured.

Don’t include symbolication information or source file line numbers in messages. The system automatically captures this information.

But I have yet to be able to find any way of viewing these supposedly captured values. In the Console app I can see subsystem, category, process ID, etc, but nothing about file and line.

And the command line tool similarly appears to lack any options for displaying this information (unless I'm missing something).

Anyone figured it out yet?

回答1:

I don't think it's available in Swift yet, although you can see file and line number in C / C++ in Terminal. See Apple forum here.

I tried something similar to what's inside the forum by creating a simple command-line tool Xcode project:

import Foundation
import os.log

os_log("rrrr")

and type the following in Terminal: log stream --source --predicate 'eventMessage contains "rrrr"', and I got this:

Timestamp                       Thread     Type        Activity             PID    
2017-02-18 17:58:46.012381+0700 0x5067d    Default     0x0                  5637   <testLogSwift`_swift_os_log> rrrr

in contrast to what I got in C/C++ version, which shows the file and line number:

Timestamp                       Thread     Type        Activity             PID    
2017-02-18 17:55:05.056103+0700 0x4aa01    Default     0x0                  5218   <testLogging`main (main.cpp:13)> qqq

来源：https://stackoverflow.com/questions/40757530/how-to-find-source-file-and-line-number-from-os-log