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Programming-Idioms

  • C#

Idiom #109 Number of bytes of a type

Set n to the number of bytes of a variable t (of type T).

int n = sizeof(T);

n is the size in managed memory of built-in value type (numeric types, char, and bool) T. Permitted in safe contexts.

In a safe context, sizeof is only permitted for built-in value types. Because there is no corresponding type parameter constraint, the operand of_sizeof cannot be a type parameter in a safe context.
using System.Runtime.InteropServices;
int n = Marshal.SizeOf(t);

Marshal.SizeOf() returns the size of a type or object if it were to be marshalled to unmanaged memory.
int n;
unsafe
{
    n = sizeof(T);
}

n is the size in managed memory of unmanaged type T or type parameter T constrained to unmanaged types.

Unmanaged types are built-in value types, enums, pointers, and structs with fields that are all unmanaged types.
N : Integer := (T'Size + 7) / 8;

T'Size returns size of T in bits. It is the minimum number of bits required to store an object of that type.
Divide by 8 to convert to bytes
New implementation...
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programming-idioms.org 
int n = sizeof(T);
int n = Marshal.SizeOf(t);
int n;
unsafe
{
    n = sizeof(T);
}
N : Integer := (T'Size + 7) / 8;
n = sizeof (t);

std::size_t n = sizeof(t);
auto n = T.sizeof;
n = c_sizeof(i)
var t T
tType := reflect.TypeOf(t)
n := tType.Size()
<T> int bytes(T t) {
    String s = t.getClass().getSimpleName();
    return switch (s) {
        case "Boolean" -> 1;
        case "Byte" -> Byte.BYTES;
        case "Short" -> Short.BYTES;
        case "Character" -> Character.BYTES;
        case "Integer" -> Integer.BYTES;
        case "Float" -> Float.BYTES;
        case "Long" -> Long.BYTES;
        case "Double" -> Double.BYTES;
        default -> -1;
    };
}
n := SizeOf(T);
use Devel::Size qw(total_size);
my $n = total_size $t;
n = pympler.asizeof.asizeof(t)
n = getsizeof(t)
n = ObjectSpace.memsize_of(t)
let n = std::mem::size_of::<T>();