I found this https://www.freebasic.net/wiki/TblComparisonC buried in a forum post by MrSwiss.
Along with my other little toy I found called Flowgorithm, very handy for beginners like me (well, I'm not really a beginner, but certainly "beginner" level) trying to make sense of the wealth of C code out there and attempting achieve a similar result in FreeBasic.
C to FB Cross reference
Re: C to FB Cross reference
Yes, pure C is pretty easy to translate to FB. It's nearly 1:1 equivalent. However knowing that doesn't always help because most C code heavily uses macros and defines, which are a lot more tricky to figure out as many of them are defined by the compiler itself based on the platform and environment it runs on. And many C programs use dozens of header files with lots of inter-dependencies. Even with automated translation tools it can be tricky.