dev log 14

Since I am free for a couple of weeks I've been looking around for open-source projects to contribute to. I sent a toot out on merveilles asking for suggestions for interesting and active projects on GitHub, written in C that I could help out with, but didn't find any that I could meaningfully contribute to in a couple of weeks. I saw that there were a lot of active projects in golang and I had been interested in learning the language for a while, so I'd decided on going through their wonderful tour of the language and then find some go projects that I could contribute to after my internship. I know it's stupid but for some reason it made sense to my caffinated brain at midnight. That's when I got a ping from neauoire. He's planning on re-writing noodle in ANSI C and gave me the opportunity to help out, WHICH IS AWESOME! We'll be porting the code from Javascript and will be using the SDL library to make it. So that's what I've been getting acquainted with since yesterday.

I've spent 4 hours dealing with a stupid bug, so it's only natural that I'll explain what it was. There are 3 basics involved with working with any game library usually.

The first 2 went smoothly. It's the thrid step that was being the issue.

/* Function to free all resources */
bool close()
{
	/* Free the surface attached to the window */
	SDL_FreeSurface(surface);
	surface = NULL;

	/* Destroy the window */
	SDL_DestroyWindow(window);
	window = NULL;

	/* Gracefully quit out of SDL */
	SDL_Quit();
}

This lead to the following error

free(): double free detected in tcache 2
[1]    13472 abort (core dumped)  ./demo 

The reason I call this a weird bug is because if I throw all the code into main() and run the exact same code. It runs fine. As soon as I modularize the code, keeping the logic of the program same, but separating the code into functions, I get this error.

It took in a while to realize what the problem was, and it's a stupid problem, it's the name of the function that's the issue. Calling the function to free the resources close() conflicted with the system call for close. Changing the function name to quit() solved the issue.

Yeah, definitely a weird one! Now onto writing the actual port for the project. You can find the code on GitHub here.

Last Edited On: 2020, 8, 19