printf

ile Cosmopolitan uses a one-function-per-filename organization. Cosmopolitan's fvprintf locks the file (which nolibc doesn't need to do) then calls vfprintf_unlocked which calls __fmt at https://github.com/jart/cosmopolitan/blob/master/libc/fmt/fm... , which is the actual implementation. It look very different from NOLIBC's. Okay, so perhaps that's they way now but not at the beginning? We can also go back to Cosmopolitan's original implementation and see how vfprintf goes through https://github.com/jart/cosmopolitan/blob/c91b3c50068224929c... to call "palandprintf", which https://github.com/jart/cosmopolitan/blob/c91b3c50068224929c... says is copyright "Marco Paland" from 2014-2019. That's a few years older than the start of nolibc, available from https://github.com/mpaland/printf , and part of https://github.com/embeddedartistry/libc , a "libc targeted for embedded systems usage". Thus, multiple factors seem to agree that nolibc code is not used in the Cosmopolitan library.