Before asking that, I've tried various tests and asked it on the forum (
http://gmc.yoyogames.com/index.php?showtopic=623177&hl= )
I'm not sure to do the things right, but if I correctly understand the techblog it seems there is a bug : as said I'm a very very newbie in the GM world (and don't speak very well english :P ) but according this techblog
http://www.yoyogames.com/tech_blog/48, debugoutput <filename> : sends debug messages and console output to the filename.
I've tried many times, from an empty project or from the first tutorial provided with GMStudio but this only provides me the console output, not the debug messages.
Example: I create a new project, with only an empty room. In the creation code of this empty room, I put this code
show_debug_message("This is a test message, with the show_debug_message function !");
I tried same thing by adding another message in the bounce action of the clown, in the first tuto.
When I run the game inside GMS, in debug mode, the messages are correctly shown in the debug window, and at the bottom of the compile frame.
Then, I compiled the project to Windows target on .zip format.
When I launch the game with the command line parameter -debugoutput debug.txt, the file includes the console messages but none from show_debug_message !
Can you point to me where I'm wrong ?