• Python

buf = bytearray(1000000)

• C#

var buf = new byte[1000000];

• Ada

type Byte is range 0 .. 255
  with Size => 8;
      
type Byte_Array is array (Positive range <>) of Byte;  
      
Buf : Byte_Array (1 .. 1_000_000);

• C

void *buf = malloc(1000000);

• C++

vector<byte> _buf(1'000'000);

• D

void[] buf = GC.malloc(1024 * 1024)[0..1024 * 1024];

• D

void[] buf = malloc(1024 * 1024)[0..1024 * 1024];

• Dart

var buf = BytesBuilder().addByte(1000000);

• Fortran

  integer(kind=c_int8_t), dimension(:), allocatable :: a

  allocate (a(10**6))

• Go

buf := make([]byte, 1_000_000)

• Haskell

createBuf :: Int -> IO (V.IOVector Word8)
createBuf n = V.new n

main :: IO ()
main = do
  buf <- createBuf 1000000
  return ()

• JS

let buf = new Buffer (1e6)

• Java

byte[] buf = new byte[1000000];

• Java

byte buf[] = new byte[1_000_000];

• Java

byte buf[] = new byte[(int) 1e6];

• PHP

$memStart = memory_get_usage();
$buf = str_repeat("\x00", 1000 * 1000);
$memEnd = memory_get_usage();
echo $memEnd - $memStart, PHP_EOL;

• Pascal

var
  buf: Pointer;
begin
  buf := GetMem(1000000);
end;    

• Perl

my $buf = ' ' * 1_000_000;

• Ruby

buf = (' ' * 1_000_000).bytes

• Rust

let buf: Vec<u8> = Vec::with_capacity(1000000);