The fixed size int types int32_t and friends weren't introduced until C99. Microsoft held out until 2013 before it put <inttypes.h> into Visual Studio!

So there has been a really long time in C's evolution where we haven't had fixed size types which has been a super annoying mess of #ifdefs in portable code.

The variable size ints have allowed some super weird architectures though. I remember looking at the datasheet for the Motorola 56000 DSP and noting that the C compiler set char = short = int = 24 bits! That was because the hardware could not address anything smaller than 24 bits. I think long could be 48 bits.