Newline in windows

Question

When I use \r\n in Windows, to print a newline in a file, it works if the file is <anyfile>.v, i.e., it's extension is .v. But if the file extension is changed to .ucf, it starts printing some garbage. I do it through Java code. Any help?

.v is a verilog file and .ucf is a Xilinx propietory constraints file. Both are handled by Xilinx software.

On running,

import java.io.*;
public class ucf {
public static void main(String[] args) throws IOException {
FileWriter output = new FileWriter("sample.ucf");
output.write("foo\r\n\bar\r\n");
output.close();
}
}

garbage is produced.

Please tell us what `.v` and `.ucf` files are. Presumably they're handled by a specific program, which gets to decide what to do with them. — Jon Skeet, Nov 12 '13 at 12:55
`.v` is a verilog file and `.ucf` is a Xilinx proprietory constraints file. They both are handled by Xilinx software. — kamalbanga, Nov 12 '13 at 12:57
@kamalbanga Then this is a case for Xilinx support, not for SO. — Ingo, Nov 12 '13 at 12:59
@Ingo but you yourself said that Java does not care about file extensions. — kamalbanga, Nov 12 '13 at 13:01
@kamalbanga Right, it doesn't. So, there **will** be "\r\n" in the Xilinx file, but the problem seems to be that Xilinx cannot handle this. — Ingo, Nov 12 '13 at 13:02
@kamalbanga Please provide a tiny program that creates an .ucf file and prints "foo\r\nbar\r\n", and then lets see how it is garbage. — Ingo, Nov 12 '13 at 13:07
@kamalbanga And if you now change the filename to "sample.v" the file contents is different? Have you verified this? — Ingo, Nov 12 '13 at 16:28

lance-java · Accepted Answer · 2013-11-12T13:21:16.577

3

Sounds like you are writing to a Writer or a PrintWriter.

Writers require a CharSet (eg UTF-8) to convert characters to binary data. If you didn't explicitly provide a charset when constructing your Writer, the JVM's default charset will be used.

I'm guessing that you write the file using one charset and Xilinx is reading the file using a different charset thus causing garbage in Xilinx.

Note that \r\n is not standard across all operating systems. To get the OS's newline at runtime you can use System.getProperty("line.separator") instead of hard coding.

edited Nov 12 '13 at 13:21

answered Nov 12 '13 at 13:08

lance-java

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+1 Nicely guessed. I whish posters would expend half of that energy to formulate their questions and provide examples of code that behaves wrong. – Ingo Nov 12 '13 at 13:09
Yeah, since I usually use raw streams, I didn't think of the whole Writer issue. Good call. – MadConan Nov 12 '13 at 13:11
@lance thanks for `System.getProperty`, exactly what i needed :) – kamalbanga Nov 12 '13 at 13:20

Newline in windows

1 Answers1