I am a student currently learning the C programming language through a book called "C Primer Plus, 5th edition". I am learning it because I am pursuing a career in programming for embedded systems and devices, device drivers, low-level stuff, etc. My question is very simple, but I have not yet gotten a straight answer from the textbook & from various posts on SO that are similar to my question.
How do you determine the size of integer data types like SHORT, INT, or LONG? I know that this is a simple question that has been asked a lot, but everyone seems to answer the question with "depends on architecture/compiler", which leaves me clueless and doesn't help someone like me who is a novice.
Is there a hidden chart somewhere on the internet that will clearly describe these incompatibilities or is there some numerical method of looking at a compiler (16-bit, 24-bit, 32-bit, 64-bit, etc) and being able to tell what the data type will be? Or is manually using the sizeof operator with a compiler on a particular system the only way to tell what these data types will hold?
You just need the right docs, in your case you need the document that defines the standard, and you should name at least 1 version of it while asking this kind of questions; for example the C99 is one of the most popular version of the language and it's defined in the ISO-IEC 9899-1999 document.
The C standard doesn't define the size in absolute terms, it goes more for a minimum size expressed in bytes, and sometimes not even that.
The notable exception is char, which is a type that is guaranteed to be 1 byte in size, but here it is another potential pitfall for you, the C standard doesn't defines how big a byte is, so it says that char is 1 byte, but you can't say anything for sure without knowing your platform.
You always need to know both the standard and your platform, if you want to do this programmatically there is the limits.h header with macros for your platform .