Casting to unsigned without specifying a type

Question

#include <stdio.h>

int main(){
  ssize_t a= -1;
  size_t b = (unsigned)a;
  return 0;
}

a is 8 bytes all set to 1, however b becomes a 4 byte number when casted to unsigned without doing a proper (unsigned size_t), why is that? why doesn't it turn into an 8 byte unsigned variable?

Answer 1

unsigned is short for writing unsigned int, so unsigned and unsigned int are the same type.

unsigned size_t does not exist; size_t is already unsigned.

why doesn't it turn into an 8 byte unsigned variable?

Because ints are commonly 32 bit or 4 bytes.

If you want fixed width integers you can use stdint.h which defines uint32_t, int32_t etc.