Malloc never fails, but you might die if you touch the memory. In general, modern OSes don't have a good story about exhausting available memory beyond "let's kill a bunch of processes to free up memory".
malloc can fail, even on default linux (overcommit enabled), if you go above the process's vmem limit for instance (because 32b or rlimited). And of course not all OS overcommit, Windows famously does not.
malloc can fail, even on default linux (overcommit enabled), if you go above the process's vmem limit for instance (because 32b or rlimited). And of course not all OS overcommit, Windows famously does not.