View Full Version : C++ I/O on Linux (Ubuntu)

February 23rd, 2008, 06:54 PM
Hi, I'm learning C++, moving from Java.
I wonder what libraries do C++ developers use on Ubuntu when developing apps? Are they using POSIX libraries or using some kind of wrappers through Glib (or something else)?
I got to the point where I can display widgets/dialogs (through Gtkmm) and now I wanna learn using Files. Any link or hint would be appreciated..

February 23rd, 2008, 07:24 PM
Look at my wiki for learning C++.

(Specifically, look into iostream and fstream)

February 23rd, 2008, 08:15 PM
I found
For instance, it turns out that finding out the current dir is as easy as

ustring sCurrentDir = getcwd( 0, 0 );

So far "Glib" seems to be easier than Java! Cool!

February 23rd, 2008, 08:43 PM
never had problems with Javas Filestream and getPath() or getAbsolutePath()...

February 23rd, 2008, 10:35 PM
getPath & getAbsolutePath just get the path of _a_ dir, while I was talking about the current dir.
The System.getProperty( "user.dir" ) doesn't always work as one might wish.
When your app is a jar you actually have troubles determining the current dir, I found the solution to this issue not so long ago, which is pretty weird, you even have to take care of the OS and the file encoding, the only robust hand-coded implementation I did is this:

URL url = thisClass.getProtectionDomain().getCodeSource().ge tLocation();
boolean isWindows = System.getProperty( "os.name" ).toLowerCase().indexOf( "windows" ) > -1;
try {
String sPath = url.getPath();
if( isWindows ) {
sPath = URLDecoder.decode( sPath, "UTF8" );
} else {
sPath = URLDecoder.decode( sPath, System.getProperty( "file.encoding" ) );
File f = new File( sPath );
if( !f.exists() ) {
Log.tell( "file doesn't exist: " + f.getPath() );
return null;

if( !f.isDirectory() ) { //then it's the .jar file and we need to get it's parent file
parentDir = f.getParentFile();
} else {
parentDir = f;
} catch( Exception exc ) {
report( exc );

I wouln't call it a trivial solution..
Now compare it to the solution in Glib :)

February 24th, 2008, 12:53 PM
you are my hero,

i noticed with the other project that you tend to use strange or more complicated solutions that actually needed:


February 24th, 2008, 01:59 PM
Please read my last post :) You didn't read it carefully, did you :)
If you're an experienced Java Developer you should understand why
doesn't always work.

February 24th, 2008, 04:00 PM
well there are dozen of options to solve a single problem. So the scope or the factors which determine which solution to choose differ a lot.

since i don't know your problem or more your desired solution and towards which domain u works its hard to tell. Buts its alright. Good luck with glib and C++.