I am pretty sure I have seen this before, but I haven't found out / remembered how to do it. I want to have a line of code that when executed from the Delphi debugger I want the debugger to pop-up like there was a break point on that line.
Something like:
FooBar := Foo(Bar);
SimulateBreakPoint; // Cause break point to occur in Delphi IDE if attached
WriteLn('Value: ' + FooBar);
Hopefully that makes sense. I know I could use an exception, but that would be a lot more overhead then I want. It is for some demonstration code.
Thanks in advance!
To trigger the debugger from code (supposedly, I don't have a copy of delphi handy to try):
asm int 3 end;
See this page:
http://17slon.com/blogs/gabr/2008/03/debugging-with-lazy-breakpoints.html
As Andreas Hausladen stated in comments to that artice, Win32 API DebugBreak() function is less DOS-ish and works equally well.
Related
I use Delphi RAD Studio 2010 and DecimalRounding_JH1.pas from http://cc.embarcadero.com/item/21909.
It works good, but I don't know why, in some old machines (Pentium IV with Windows XP SP3), the round fails after access to printer.printerindex. I have checked that the problem not is Windows XP due it works in other machines with this OS.
I have made a simple project that round an extended value with DecimalRounding_JH1 (drHalfUp) with two decimals (1.105 -> rounds to 1.11). But If I read printer.printerindex, then 1.105 rounds to 1.10).
I thought it could be the "FDIV bug", but compiling with "FDIV safe" doesn't resolve the problem.
The code:
var d1,d2:extended;
i:integer;
begin
d1:=1.105;
d2:=DecimalRounding_JH1.DecimalRoundExt(d1,2,drHalfUp);
memo1.lines.add(FloatToStr(d2)); // --> shows 1.11 (OK)
i:=Printer.printerindex;
d2:=DecimalRounding_JH1.DecimalRoundExt(d1,2,drHalfUp);
memo1.lines.add(FloatToStr(d2)); // --> shows 1.10 (ERROR!!!)
...
I know that it is very strange, but I've tested it and It's as I said.
What could I do?
Edited:
If I add Printer.printerindex:=1; (for example) before i:=Printer.printerindex; then again it works good. Reading printer unit, the difference is about execute "SetToDefaultPrinter" or not:
function TPrinter.GetPrinterIndex: Integer;
begin
if FPrinterIndex = -1 then SetToDefaultPrinter;
Result := FPrinterIndex;
end;
thanks in advance.
Certain parts of the system printer libraries have a rather nasty habit of modifying the 8087 control word. You should restore it to its default value after using methods and properties of Printer.
For example, you might write it like this:
Set8087CW(Default8087CW);
The comments in my codebase suggest that you only need to do this after the VCL printer code has been initialized for the first time. So you could deal with this in your program's startup. Read Printer.PrinterIndex and then immediately set the control word to its desired value.
I am debugging a DirectShow filter I created with the DSPACK code library using Delphi 6 Pro. When a breakpoint I set is hit in one particular unit named BaseClass.pas, and I begin tracing, the Execution Point jumps to strange places in the source code. This usually indicates that the source code being traced does not match the source code that was compiled into one of the packages being used by the Delphi application. Oddly enough it is only the BaseClass unit since I have traced other units belonging to the DSPACK code library and they do not exhibit this problem. I am not using run-time packages.
I scanned my disk and found only one copy of BaseClass.dcu with a modification date equal to the last time I built the program. I have not modified the source for that unit or any other belonging to DSPACK. Since my Filter is part of the main application this indicates that BaseClass.pas would be subject to a dual use situation since it is used to build the DSPACK component package (dpk), and is also referenced by my main application directly via the TBCSource object my Filter descends from. Note, I did try adding the unit PAS file directly to my Project but that didn't fix anything.
I also went back and re-opened each of the DSPACK package files and did a full re-build. None of this helped. Is there something else I can try to get the source synchronized with the compiled image of the BaseClass unit? Or is a different problem altogether and if so, what is it and how can I fix it?
Sometimes this happens when code is copied/pasted from web pages or other sources, and the lines don't end with CR/LF pairs (#13#10 or 0x0D0A, standard for Windows) but end in only LF (#10 or 0x0A, typically the line ending in *nix systems) or CR (#13 or 0x0D, typical with Mac OSX/iOS). The incorrect line terminators confuse the debugger - this has been an issue for the past several Delphi versions.
You can sometimes fix this by opening the source file using a text editor like Notepad, making a small meaningless change (insert and then delete a blank line, for instance), and then save the file.
I had same problem and made a similar utility. Fixed it.
Basically, just this:
procedure adjustCRLF(filename : String);
var
strList : TStringList;
begin
strList := TStringList.Create;
try
strList.LoadFromFile(filename);
strList.Text := AdjustLineBreaks(strList.Text);
strList.SaveToFile(filename);
finally
strList.Free;
end;
end;
There is another way this can happen: if the IDE erroneously opens another source file with the same name (but different, such as an earlier version) then all the debug points will be incorrect, and the debugger will even allow you to step through the incorrect file.
I've seen Delphi 7 do this once.
Make sure that when you rebuild it, that in the compiler options for your project that you have "Debug Information" turned on. In fact, most of the options under Debugging should be set in your project's Compiler options.
Also, if you haven't already, restart Delphi.
I am a long time Delphi dev and in the past I use a third party tool for logging and debugging while developing (called Smart Inspect) however now that I've upgraded to Delphi XE I want to try and use the IDE for debugging.
My question is, given a function like
procedure MyFunction;
var
str : string;
begin
str := 'Foo';
//Debug, show value of str?
str := AnotherFunction(str);
//Debug, show value of str?
end;
how can I debug and get the value of str, without doing stupid things like
showmessage(str);
if there is a video somewhere (or article) then I am more than happy to read.
Is there a way to watch/output the value of variables.
If you want to use the IDE Debugger only, then do the following:
put a breakpoint somewhere
right click on the breakpointr circle and choose "Breakpoint Properties ..."
press "Advanced" button to show more options
uncheck "Break" checkbox
then use "Log message" and "Eval expression" edit boxes to enter trace values
Such messages will be send to "Event Log" debugger pane. Right click on the pane and choose "Properties". There you can filter ("Messages") / hilight ("Colors") the trace messages as you whish.
Well, Delphi XE comes with CodeSite logging, but I get the feeling you're talking about the debugger itself.
If you place a breakpoint in a routine, it will break to the debugger when it hits it. From there, you've got a Local Variables pane and a Watches pane along the left side of the IDE. Local Variables will show the value of all locals, and Watches lets you set up expressions whose value it will keep track of.
You can also get something similar to a watch, but with more detailed information (especially for structured types such as objects) by using Inspect (Alt-F5). Also, the Evaluate/Modify (Ctrl-F7) will allow you to type in expressions and evaluate them. It's not quite as detailed as Inspect, but it gives you a lot more flexibility.
If you familiarize yourself with these tools, you'll find debugging much easier.
1) You can use OutputDebugString Function to output string to debug window
2) You can use CodeSite Express. I recommend video from CodeRage 5 as a starting point for using CodeSite
Other answers are all correct.
My personal favorite technique (same as the answer by da-soft) is to create a breakpoint, that logs a message to the event log, containing a value that I want logged, and does not actually "break" (that is, execution continues without you hitting the Run icon). Then every time that line of code is reached, I get my message, and my values in the log. Since I can go back and read the history, as well as see the current values, I find this more useful than merely using the debugger watch window.
But since Delphi XE includes CodeSite, you can go far beyond what expression evaluation in breakpoints does for you. Code Site however requires that you modify your code to add some logging. But it's much better than a message box.
You can also use OutputDebugString(PChar(s)) to output any string to the debugger. Since this can contain whatever you want, it's a very nice way to debug but not show stuff to the end user.
In many of my applications, I have a special trace buffer, which is circular (that is, it keeps only the last 500 or so lines). When ever I see a problem, not only do I get a stack traceback, I also save that in-memory trace log, so I have some history on what was going on just before my problem.
You can also check out the Log 4 Delphi project.
I prefer debugger hints. After breaking to the debugger move your mouse to the "str" anywhere in your code and you will see its current value. Also you can highlight some statement by a mouse and evaluate it. For example highlight "AnotherFunction(str)" and place your mouse over it.
Nothing wrong with any of the other answers but I just wanted to add these useful functions.
procedure DebugString ( const s : string ) ; overload ;
begin
{$IFDEF DEBUG}
OutputDebugString ( PChar ( s ) ) ;
{$ENDIF}
end ;
procedure DebugString ( const s : string ; args : array of const ) ; overload ;
begin
{$IFDEF DEBUG}
OutputDebugString ( PChar ( Format ( s , args ) ) ) ;
{$ENDIF}
end ;
I have a problem with the background compiler in Delphi7: in my project there is a single line of code that causes the background compiler to stop with an error message so that no CodeCompletion is possible. The normal compiler and the syntax check have no problem with this code and the resulting application is correct.
My question is if there is any way to skip this codeline when the background compilation is performed (e.g. compiler directive).
Example code to reproduce the error:
procedure ProduceKibitzError;
var
v : Variant;
begin
v.End; // This line stops kibitz compiler
end;
This code is placed in a unit "Error.pas" which is used in the main unit.
If you try to call CodeCompletion in the main-unit, it stops with the message "Error.pas could not be compiled" (real message is in german).
Interestingly the error only occurs until the project is compiled or syntax check is performed for the first time.
After compilation the CodeCompletion is working and Delphi has to be restarted to reproduce the error.
Update:
Adding an empty Assembler block with an end label is a solution for the problem.
Here is the changed example code that doesn't stop the background compiler:
procedure ProduceKibitzError;
var
v : Variant;
begin
asm
##END:
end;
v.End;
end;
Many thanks,
Christian
The background compiler does not do procedure body analysis when parsing to get to the position of the cursor. Instead, it uses simple syntax matching (such as begin/end pairs). If simple syntax matching indicates that the final end in the unit has been met, then it exits early.
This is what's happening with your example. The first End token is not escaped by the late binding logic because it's not being parsed by the real expression compiler, and instead it's being read as the end of the procedure. The second end looks like the end of the unit, and the background compiler never sees any further.
Added: You might try adding an empty asm/end block to this routine. It prevents the kibitz compiler skipping procedure analysis. Graphics.pas has an asm/end block with an ##end label, and the compiler handles asm/end blocks specially because of it.
Looks like the background compilation doesn't know what to do with the late binding.
Do you know which COM type library is used to make the call on the object? It would benefit both the compilation and the application's performance if you could export and use the pascal-wrapper unit based on the type library. (See Import Type Library option in the main menu)
Try escaping the token with & ?
so
v.&end;
I'm using TNMHTTP in Delphi to retrieve the code from a webpage. The code is relatively simple:
NMHTTP1 := TNMHTTP.Create(Self);
NMHTTP1.InputFileMode := FALSE;
NMHTTP1.OutputFileMode := FALSE;
NMHTTP1.ReportLevel := Status_Basic;
NMHTTP1.TimeOut := 3000;
URL := 'http://www....';
NMHTTP1.Get(URL);
S := NMHTTP1.Body;
I am catching exceptions in a try/except block, but that is not the problem.
The problem is that on executing the NMHTTP1.Get method when the URL is a redirect, that method does not return and the program hangs. This is despite the fact that I've put a timeout of 3000 seconds in.
So I see three possible ways of solving this (in order of easiest to hardest for me to modify my program):
Do whatever is necessary to get the NMHTTP1.Get method to respond.
Do some sort of check in advance of the NMHTTP1.Get statement to see if the URL is a redirect and get the URL it is redirecting to.
Use another method to get a webpage using Delphi. When I wrote this, I used Delphi 4 and did not have Indy. I now have Delphi 2009, so I would be willing to use something that works in it (maybe INDY) if a simple #1 or #2 answer is not available.
I would love to get an answer from someone that will work for me. Thanks in advance.
I would avoid the NetMasters controls, period.
Instead, you can use Indy's IdHTTP component, which has a RedirectMaximum property (defaults to 15) and an OnRedirect event in case you want to track the details.
I can advice you to switch to Indy. They are great for a lot of network protocols (with the exception of the IRC protocol). There are nice examples included so you can examine the working examples yourself.
Also have a look at http://www.indyproject.org/index.en.aspx for more information on indy.