cross platform logging in Golang

I am developing a Go program on a Mac which has Parallels installed with Windows so that I can test on both platforms. My program works well. I can compile a Windows ".exe" file on my Mac and run it from Windows and it works well except the log file.

I have set the logger to write its output to a file like so:

log.SetOutput(projectsLog)

Where projectsLog is declare above it as shown below:

projectsLog *os.File

I am using log.Printf statements since I want formatted output. An example is shown below:

log.Printf("Error: wrong Hra Class value %s in row %v for project/path %s", hraClass, (rowNum + 1), testDir)

This is working great on Mac. Each line using log.Printf is logged on a separate line, but on Windows the line breaks do not show and I get one lines without line breaks. I am well aware of "\r" and "\r\n" difference between unix and windows. But I thought that log.Printf will behave appropriately based on the platform it is run on?

If my assumption is wrong then what are some of the options that I have to make sure that the log file is readable on Windows? If I can, I do not want to pass flags, e.g., -platform windows or some such thing. Can this be handled in a transparent manner?

As noted, the fmt package always uses \n as the newline "sequence" regardless of the OS (on Windows too). The log package uses fmt under the hood, so the same applies to log too. When functions that do not end with ...ln() are called (e.g. log.Printf()), a \n will be printed explicitly as documented at Logger.Output() (to which log.Printf() forwards to).

Just deal with \n as the newline. If you do need to print \r\n, you have to handle that manually by appending a \r character at the end of the format string, e.g.:

log.Printf("This will be terminated by CR+LF\r") // \n is appended automatically

You may create a wrapper function for it:

func winprintf(format string, a ...interface{}) {
	log.Printf(format+"\r", a...)
}

Note that this however will only print \r\n at the end of the log entry; but if you use \n inside the format string or the arguments are strings (or will result in a string by calling their String() method) containing \n, those will not turn into \r\n automatically. You may use strings.Replace() to handle those too.