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(In reply to beuc from comment #0)
> Hi,
> 
> I see that when using SDL_LOG_PRIORITY_DEBUG, SDL_SetError() not only sets
> the current error but also prints it out.
> This sounds like a good idea at first, but in practice I get flooded by
> errors that I specifically handled in my code.
> For instance, whenever I query SDL_GetColorKey, even when I handle the case
> when the result is < 0, I get a "DEBUG: Surface doesn't have a colorkey" in
> my debug logs.
> (that wasn't the case until recently because previously it just returned -1
> without calling SetError())
> 

This is what the DEBUG category is for, debugging, it would be useless if it didn't print all the errors that happened. 

> That was very misleading so I would suggest not printing out errors when the
> user didn't ask. Instead, possibly a different flag/function to make SDL
> trace all the SetError()s.

By default none of these flags are on, so the user MUST be asking for it to be printed. Alternatively you could use GetError() after a function that might do a SetError() (And that is the proper way using SDL imo)

Hi,

I probably didn't explain the use case properly:

- Context: my game uses the SDL_Log function with various log levels to trace errors. There is a game setting to set the log level to "debug" and get legitimate game errors while developing the game engine or working on an extension.

- When there is an error, SDL sets the error with SDL_SetError. Depending on the situation, my game queries SDL_GetError and prints it out (with the appropriate log level), or deal directly with the error and do not print it out.
E.g.: when calling SDL_GetColorKey, if there's no color key in the picture, then the game runs an alternate true-color processing, and nothing is printed.

- Now when the log is set to debug, SDL will print out every SetError, including the ones for errors/warnings that my game handles. This means the log is cluttered with both non-handled and handled errors.

Summary: the log level needs to trigger printing errors when SDL (or the game) actually prints errors, not when SDL merely sets the error message for later use (SDL_Log vs. SDL_SetError).

(btw, are you from the SDL team?)

(In reply to beuc from comment #2)
> Summary: the log level needs to trigger printing errors when SDL (or the
> game) actually prints errors, not when SDL merely sets the error message for
> later use (SDL_Log vs. SDL_SetError).

But the log level actually does that, the thing is there is a SDL_LogDebug in the SetError function. You could try using a custom category, https://wiki.libsdl.org/SDL_LOG_CATEGORY#Remarks, for your engine/game specific debug logs in conjunction with SDL_logMessage().

> (btw, are you from the SDL team?)

No, I am not.

I know there is a LogError call in SetError and that's basically what this bug is about.

If there's a real error in SDL I want to know about it, so filtering out SDL errors entirely is inadequate.

I issued this bug to discuss the issue with the SDL developers, I am not interested in explaining the issue to other users or getting support, there's a mailing list for that.