While coding tonight, I spent *at least* 20 minutes trying to figure out why my program was crashing in strtok_r. Turns out I forgot that strtok (and strtok_r) modify the string in-place (with null bytes), and I was passing in a string literal.

In C, "string literals" are stored in a special read-only bit of the program, so if you try to modify them your program crashes. I was calling a function several levels up with a string literal trying to test functionality and it kept crashing with sigbus. Wee. Lesson relearned ;)