Understanding sizeof(char) in 32 bit C compilers

Question

(sizeof) char always returns 1 in 32 bit GCC compiler.

But since the basic block size in 32 bit compiler is 4, How does char occup

Answer 1

Because of optimisation padding is added so size of an object is 1, 2 or n*4 bytes (or something like that, talking about x86). That's why there is added padding to 5-byte object and to 1-byte not. Single char doesn't have to be padded, it can be allocated on 1 byte, we can store it on space allocated with malloc(1). st cannot be stored on space allocated with malloc(5) because when st struct is being copied whole 8 bytes are being copied.