Just want to put some links here on the standard sources of the C language and Fortran. Sometimes it’s reaffirming to read the official documents suggesting how the compilers should interpret the language. In general this page
http://gcc.gnu.org/readings.html ,
has most of those references, including info on chips. Although the standards aren’t officially released very often, there seems to be constant communication discussing future updates.
The current standard of C is C11, public version:
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf .
Links to Fortran standards:
https://gcc.gnu.org/wiki/GFortranStandards#Fortran_77 .
This compact list of gnu packages is great:
https://www.gnu.org/software/software.html,
search the package, its documentation, and download it into a .txt file (few exceptions). I just use vim to browse them. The g77 docs have some useful notes on interoperability between C and Fortran.