Tcl

Socket Receive String Until Specific Byte Value is Received

Demonstrates the Chilkat Socket ReceiveStringUntilByte method. Tcl

load ./chilkat.dll

set success 0

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

set sock [new_CkSocket]

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

set useTls 0
set port 4242
set maxWaitMs 5000
set success [CkSocket_Connect $sock "tcpbin.com" $port $useTls $maxWaitMs]
if {$success == 0} then {
    puts [CkSocket_lastErrorText $sock]
    delete_CkSocket $sock
    exit
}

# Wait a max of 2 seconds for a response..
CkSocket_put_MaxReadIdleMs $sock 2000

# Send some strings, each terminated by a 0 byte.
CkSocket_SendString $sock "This is the 1st string"
CkSocket_SendByte $sock 0
CkSocket_SendString $sock "This is string number 2"
CkSocket_SendByte $sock 0

# The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
CkSocket_SendByte $sock 10

# Now let's receive what is echoed back....
# Receive each string and the NULL byte.
# The call to ReceiveStringUntilByte will receive incoming data until the lookForByte is encountered.
# The lookForByte is receive and discarded (it is not returned in the string)
set lookForByte 0
set s1 [CkSocket_receiveStringUntilByte $sock $lookForByte]
if {[CkSocket_get_LastMethodSuccess $sock] == 0} then {
    puts [CkSocket_lastErrorText $sock]
    delete_CkSocket $sock
    exit
}

puts "$s1"

set s2 [CkSocket_receiveStringUntilByte $sock $lookForByte]
if {[CkSocket_get_LastMethodSuccess $sock] == 0} then {
    puts [CkSocket_lastErrorText $sock]
    delete_CkSocket $sock
    exit
}

puts "$s2"

# The echo server will also echo back the final LF
CkSocket_ReceiveByte $sock 1
set maxWaitMs 100
CkSocket_Close $sock 100

# Output:
# This is the 1st string
# This is string number 2

delete_CkSocket $sock