lazarus/tools/debugserver/README.txt
2014-09-11 21:07:42 +00:00

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The debug server is a simple program that listens for debug messages,
and displays them in a list. The messages can be saved, cleared, it can
be paused - whatever.
It is the server part to a standard FPC unit - dbugintf. This unit
offers a simple API to send messages to a debug server (using
simpleIPC), modeled after the GExperts GDebug tool for Delphi, with
some minor enhancements.
Typical usage is as follows (I stripped actual code and {$ifdef debug}):
uses dbugintf,sysutils;
Procedure BackupFile(FN : String);
Var
BFN : String;
begin
SendMethodEnter('BackupFile');
BFN:=FN+'.bak';
SendDebug(Format('backup file "%s" exists, deleting',[BFN]));
SendDebug(Format('Backing up "%s" to "%s"',[FN,BFN]));
SendMethodExit('BackupFile');
end;
Procedure SaveToFile(FN : String);
begin
SendMethodEnter('SaveToFile');
BackupFile(FN);
SendDebug('Saving to file '+FN);
SendMethodExit('SaveToFile');
end;
There are some more methods; see the FPC dbugintf help for that.
It is extremely useful when debugging GUI code with lots of events - because
you see the messages as they are sent, in a separate window which can be kept
'on top'.
It can also be used to debug server (e.g. daemons, services, CGI) applications.
The indentation of the messages (by SendMethodEnter) is intentional: if an
exception occurs, then the SendMethodExit does not happen, and you see that
something is wrong visually.