Why doesn't strace catch all file accesses?

Question

I'm trying to use strace to monitor all file accesses by g++ but it only seems to catch read accesses. Why isn't the file access for the output file shown?

Answer 1

g++ is just the frontend. It pipes the output to as directly.

Answer 2

g++ calls other programs to do part of the build. If you want strace to trace those child processes, you need to use 'strace -f'.