List of error messages

In Game Maker, quite a few run or compile-time errors can happen which Game Maker throws at you. Apart from the user-generated (using the function show_error) there is a big list of standard error messages:

Known error messages

 * Unknown variable. Variable is not initialized anywhere.
 * Array index out of bounds. You are trying to read an array index which is bigger than the maximum initialized index.
 * Wrong type of arguments. You’re feeding a function (or operator) a variable type it can’t use (real where string is needed, string where real is needed). AND it can’t automatically convert its variable.
 * Wrong number of arguments to function or script. Simply the wrong number of arguments. Read the manual.
 * Cannot assign to variable. You’re trying to assign a value to a read-only variable (variable defined by gm)
 * Trying to use non-existing surface. Like explained, the variable exists, however the surface with this id does not.. Either you use the wrong variable, or it is free in some way (see above)
 * Data structure with index does not exist. Data structure isn’t created, or it’s the incorrect data structure.
 * Error defining dll function. Many causes, but most likely caused because you’re trying to define a dll to use an argument the dll doesn’t support.
 * Unexpected error while running the game. Only pops up when starting a game. Has many causes, like failure to define dlls while starting the game (before the first draw event). Or surfaces which can’t be initialized. This also might be caused if you put error messages on “off”, and a critical error happens.