Andreas Bernauer's personal blog

Who's designing the error messages of g++? Anyways, here is a translation:

error: request for member ‘foo’ in ‘((Test*)this)->Test::_bar’, 
which is of non-class type ‘C_bar*’

means: in class Test, you've written _bar.foo, but _bar is a pointer; you need to write _bar->foo, that is, change the dot to an arrow.

Happy C++ coding!

I've just found a nice, small C compiler: tinycc. The compiler includes the actual compiler and the linker, so you don't need other external tools. The executable is only 122KB in size on my system (Fedora Core 6). I like tcc because it allows you to create C-scripts.

I found the Howto on the gcc inline assembler difficult to understand, so I wrote up the major parts here and created some kind of summary.

Today a small hint that can save you a lot of debugging time when writing shell scripts. If you start your (bash) shell script with
set -u -e
unset parameters won't expand to nothing (-u) and the script ends immediately when one command fails (-e) unless it is part of a test (if, while, ||, etc., see bash(1)).

If you want to debug your shell script, you either insert echo commands throught your script, or you can just insert
set -v -x
at the top. This will turn on verbose mode (-v) in which bash will print the input lines as they are read. The execution trace (-x) mode will print the commands after expansion but before execution, so you can check if the command is invoked the way you intended.

I thought about posting similar hints for tcsh, but who is shell scripting in tcsh anyways?

The article Memory Barrier at ridiculous fish describes an interesting observation when doing multithreading.

Assume you have a writer thread that increments two global variables continously:

while (1) {
   variable1++;
   variable2++;
}

The reader thread reads the two global variables continously:

while (1) {
   local2 = variable2;
   local1 = variable1;
   if (local2 > local1) {
      print("Error!");
   }
}

The reader thread reads the variables in the reverse order to assure that local2 <= local1, as the writer thread increments local2 after local1. If you think that this condition always holds, read the blog entry on
Memory Barrier to see why it doesn't. As you may already have guessed, you need a memory barrier to ensure this condition.

(Thanks to copton for pointing me to the blog entry.)