textCallBack
handle text output in OpenMaple
Calling Sequence
Parameters
Description
Examples
textCallBack(data, tag, output)
data
-
user_data pointer passed to StartMaple (Long)
tag
code indicating kind of text (Long)
output
output string (byte array pointer)
This OpenMaple function is part of the MapleCallBack structure passed as an argument to StartMaple.
The textCallBack function is called with typical (non-exceptional) Maple output. The output that Maple generates, for example, an intermediate result or the output from a printf statement, is passed to the textCallBack function.
The prototype for the function that you can assign to the entry in the MapleCallBack must resemble the following.
Sub TextCallBack(ByVal data As Long,
ByVal tag As Integer,
ByVal Output As Long)
The tag parameter indicates the type of Maple output. The tag parameter can take one of the following values (as defined in maplec.h).
MAPLE_TEXT_OUTPUT
A line-printed (1-D) Maple expression or statement.
MAPLE_TEXT_DIAG
Diagnostic output (high printlevel or trace output).
MAPLE_TEXT_MISC
Miscellaneous output, for example, from the Maple
printf function.
MAPLE_TEXT_QUIT
Response to a Maple quit, done, or stop command.
MAPLE_TEXT_WARNING
A warning message generated during a computation.
MAPLE_TEXT_ERROR
An error message generated during parsing or
processing. This is generated only if you
do not specify an errorCallBack function.
MAPLE_TEXT_STATUS
Kernel resource usage status (a "bytes used"
message). This is generated only if you
do not specify a statusCallBack function.
MAPLE_TEXT_DEBUG
Output from the Maple debugger.
The output parameter contains the output of the type indicated by the tag parameter. Each output string can be arbitrarily long. Most output obeys interface(screenwidth), which is initially set to infinity. Some output is not line-broken, including output generated by printf (which controls its own formatting).
A single result may be split into multiple calls to the textCallBack function. In particular, this can happen when interfacescreenwidth is not infinity. It is also true for formatted output like that generated by accessing help. A single command can generate many calls with different output tags.
The data parameter contains the same data as passed to StartMaple in the user_data parameter.
Public Sub TextCallBack2(ByVal data As Long, ByVal tag As Integer, _
Dim OutputString As String
OutputString = MaplePointerToString(Output)
If tag = MAPLE_TEXT_HELP Then
Write #2, OutputString
Else
Write #1, OutputString
End If
End Sub
' assignment to MapleCallback entry
cb.lpTextCallBack = GetProc(AddressOf TextCallBack)
' test statement that will invoke the TextCallBack
EvalMapleStatement kv, "x^2+3*x+1;"
EvalMapleStatement kv, "help(int);"
See Also
callBackCallBack
errorCallBack
interface
OpenMaple
OpenMaple/VB/API
OpenMaple/VB/Examples
queryInterrupt
readLineCallBack
redirectCallBack
StartMaple
statusCallBack
streamCallBack
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