halting problem :)

[Saaa]

My program doesn't exit..

void main()
{

..
Data data[]

createData(data);
//This proces takes a minute or two.
//data now holds about 700000 Data elements

 writefln(`Creating buffer`);
 ubyte[] buffer;
 for (int i=0; i<data.length; i++)
 {
  buffer~=format(data[i].net,`,`,data[i].name,`,`,to!(int[])(data[i].output),`,`,to!(int[])(data[i].input),newline);
  //This takes like a minute and has a peak memory usage of 680MB
 }

 writefln(`Writing file`);
 std.file.write(outFilename, buffer);
writefln(`Writing file finished`);

//The file is readily made and delta memory usage shows a few a few times 
around 20MB
//but the program doesn't stop, although 'Writing file finished' is shown.
//there is no static this or alike.
//and after 10 minutes the memory usage is about 370MB and slowly going up
//ctrl-c doesn't work anymore as well
}