Error: WndProc - nothrow

[monarch_dodra]

On Sunday, 16 September 2012 at 21:12:42 UTC, deed wrote:
> I did, but then I am not able to use writeln for debugging.
> Is this restriction something new?

nothrow just means the function itself should not *exit* with an 
exception. It is still legally allowed to call a throwing 
function, provided promises to handles (catche) any thrown 
exception. How it deals with the exception (silence/error) is up 
to it. For example:

--------
void foo() nothrow
{
     try
     {
         writeln("hello world!");
     }
     catch(Exception) { } //silence

     //doStuff
}
--------

Of course, the "try catch do nothing" writting can get old, so 
you can use std.exception's "collectException" too*;
--------
void foo() nothrow
{
     collectException(writeln("hello world!"));

     //doStuff
}
--------
*Though for me, the compiler sometimes still complains.

Or better yet, you *could* write a "debugWriteln()", which is 
marked as @trusted nothrow:
--------
@trusted nothrow
void debugWriteln(Args...)(Args args) nothrow
{
     try{writeln(args);}catch(Exception){};
}

void foo() nothrow
{
     debugWriteln("hello world!");

     //doStuff
}
--------
The @trusted is so that it can also be used inside safe functions 
(which will exhibit the same issue). With this, you can log in 
any function.