[QUERY] Understanding call flow from stdio to stub syscalls in newlib (nvptx)

Hi,

I’m a new contributor to newlib, currently working on modifying the
stub system calls in
newlib/libc/machine/nvptx/misc.c as part of my Google Summer of Code
2025 project
under GCC. The goal is to implement a memory-resident filesystem for
nvptx targets.

To facilitate this, I’d like to better understand how higher-level
stdio functions (e.g., fopen())
resolve down to these low-level syscall stubs like open().
Specifically, I’m looking for a
rough call flow or trace of function calls (e.g, fopen() --> open()),
and any relevant source
files beyond misc.c that would be helpful for understanding this
linkage within newlib.

Any guidance or references would be greatly appreciated.

Thanks and regards,
Arijit Kumar Das