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Check Whether an SSH Exit Status Was Received

Demonstrates the Chilkat Ssh.ChannelReceivedExitStatus method, which reports whether the server supplied an exit-status value for a channel. The only argument is the channel number. When it returns true, call GetChannelExitStatus to read the value.

Background: Always test this before reading the exit status, because the server is not required to send one for every channel type or command — treating a missing status as "0" would silently turn a failure into a success. Exit status is independent of EOF and CLOSE: it can arrive after EOF and either before or together with CLOSE.

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llSuccess = .F.

//  Demonstrates the Ssh.ChannelReceivedExitStatus method, which reports whether the server
//  supplied an exit-status value for a channel.  The only argument is the channel number.  When
//  it returns .T., call GetChannelExitStatus to read the value.

loSsh = createobject("CkSsh")

lnSshPort = 22
llSuccess = loSsh.Connect("ssh.example.com",lnSshPort)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
lcPassword = "mySshPassword"

llSuccess = loSsh.AuthenticatePw("mySshLogin",lcPassword)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

lnChannelNum = loSsh.OpenSessionChannel()
if (lnChannelNum < 0) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

llSuccess = loSsh.SendReqExec(lnChannelNum,"test -f /etc/hosts")
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

//  IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
//  it, this call waits forever if the server never sends channel close.
loSsh.ReadTimeoutMs = 15000

llSuccess = loSsh.ChannelReceiveToClose(lnChannelNum)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

//  The server is not required to send an exit status for every channel type or command.
if (loSsh.ChannelReceivedExitStatus(lnChannelNum)) then
    lnExitStatus = loSsh.GetChannelExitStatus(lnChannelNum)
    ? "Exit status: " + str(lnExitStatus)
else
    ? "The server did not provide an exit status."
endif

loSsh.Disconnect()


release loSsh