hi ras, thanks for that.
so, I don't know who else got stuck in `linking & loading` phase of C
compilation process. the `-lm` flag of `gcc` I guess does that.
so, preprocessing literally copy and paste the high-level C code from header
files to this (main.c), macros are replaced with compTime constant values. okay.
now, compiling to assembly, then this assembly code is compiled to final
machine/object code.
after that we do linking and loading.
I tried to study it many times but I don't understand this.