Lianja

Socket Send/Receive 16-bit Integers

Demonstrates sending and receiving 16-bit integers over a socket connection using either big-endian or little-endian byte ordering. Lianja

llSuccess = .F.

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

loSock = createobject("CkSocket")

// --------------------------------------------------------------------
// This example uses the public TCP echo service at https://tcpbin.com/
// --------------------------------------------------------------------

llUseTls = .F.
lnPort = 4242
lnMaxWaitMs = 5000
llSuccess = loSock.Connect("tcpbin.com",lnPort,llUseTls,lnMaxWaitMs)
if (llSuccess = .F.) then
    ? loSock.LastErrorText
    release loSock
    return
endif

// Wait a max of 2 seconds for a response..
loSock.MaxReadIdleMs = 2000

// Send a 16-bit integer using big-endian byte ordering (also called network byte order)
// 12022 decimal = 2EF6 hex
lnValue = 12022
llBigEndian = .T.
loSock.SendInt16(lnValue,llBigEndian)
// Send it again, because we'll read it two different ways..
loSock.SendInt16(lnValue,llBigEndian)

// The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
loSock.SendByte(10)

// Let's see hex values of the 2 bytes sent in network byte order (big-endian)
// (The echo server sends back exactly the bytes received.)
lcHexStr = loSock.ReceiveNBytesENC(2,"hex")

// In the big-ending byte order, the byte order is most significant byte to least significant,
// therefore we should see the bytes in the order 0x2E 0xF6.
? "Expecting big-endian 2EF6"
? lcHexStr

// Let's read directly to an integer..
llSuccess = loSock.ReceiveInt16(llBigEndian,.T.)
? "Expecting 12022"
? "Received: " + str(loSock.ReceivedInt)

// Consume the LF that gets echoed back..
loSock.ReceiveByte(.T.)

// --------------------------------------------------------------------
// Let's do the same thing, but with little-endian byte ordering.

? "----"

// 12022 decimal = 2EF6 hex, but little-endian byte ordering will send the bytes in the order 0xF6 0x2E
lnValue = 12022
llBigEndian = .F.
loSock.SendInt16(lnValue,llBigEndian)
loSock.SendInt16(lnValue,llBigEndian)
loSock.SendByte(10)

lcHexStr = loSock.ReceiveNBytesENC(2,"hex")

? "Expecting little-endian F62E"
? lcHexStr

llSuccess = loSock.ReceiveInt16(llBigEndian,.T.)
? "Expecting 12022"
? "Received: " + str(loSock.ReceivedInt)

// Consume the LF that gets echoed back..
loSock.ReceiveByte(.T.)

loSock.Close(1000)

// Output:

// Expecting big-endian 2EF6
// 2EF6
// Expecting 12022
// Received: 12022
// ----
// Expecting little-endian F62E
// F62E
// Expecting 12022
// Received: 12022


release loSock