Delphi enumwindowsproc

The problem is surely that your actual code differs from the code that you have shown. My guess is that in your actual code, EnumWindowsProc is a nested function: Why cannot take address to a nested local function in 64 bit Delphi?

But that is just a guess. I don't know what your real code looks like. I do know that the code in the question works correctly. This won't affect your program's correctness, but it is semantically wrong.

I would declare that type like this:. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. EnumWindows behaving oddly in bit Delphi Ask Question. Asked 6 years, 7 months ago. Active 6 years, 7 months ago. Viewed 1k times. For more information, see EnumWindowsProc.

If the function fails, the return value is zero. To get extended error information, call GetLastError. If EnumWindowsProc returns zero, the return value is also zero. In this case, the callback function should call SetLastError to obtain a meaningful error code to be returned to the caller of EnumWindows.

Controls, Vcl. Forms, Vcl. Dialogs, Vcl. ExtCtrls, Vcl. Improve this question. TLama Add a comment. Active Oldest Votes. Improve this answer. David Heffernan David Heffernan k 40 40 gold badges silver badges bronze badges.

Just a preference: but I would write GetWindowText wHandle, Title[0], Length Title ; this would make sure that it also works with dynamic arrays and doesn't fail when the length of the array changes. Mehmet No, that can't be correct. ListBox1 is an object, so both cases should pass the address of it, no? Mehmet The former passes the address of the object, the latter passes the address of a variable containing the address of the object. Sign up or log in Sign up using Google. Sign up using Facebook.

However, certain functions return values that must be stored in a buffer, and that buffer is passed to the function in the form of a pointer. In most cases, when the function description specifies that it returns some value in a buffer, null-terminated string buffer, or pointer to a data structure, these buffers and data structures must be allocated by the application before the function is called.

In many cases, a parameter may state that it can contain one or more values from some table. These values are defined as constants, and they are combined using the Boolean OR operator. The actual value passed to the function usually identifies a bitmask, where the state of each bit has some significance to the function. This is why the constants can be combined using Boolean operations. For example, the CreateWindowEx function has a parameter called dwStyle which can accept a number of constants combined with the Boolean OR operator.

Conversely, when a function states that it returns one or more values that are defined as specific constants, the return value can be combined with one of the constants using the Boolean AND operator to determine if that constant is contained within the return value.

If the result of the combination equals the value of the constant, then that constant is included in the return value. Originally, software only needed a single byte to define a character within a character set. This allowed for up to characters, which was more than plenty for the entire alphabet, numbers, punctuation symbols, and common mathematical symbols.

However, due to the shrinking of the global community and the subsequent internationalization of Windows and Windows software, a new method of identifying characters was needed. Many languages have well over characters used for writing, much more than a single byte can describe. Therefore, Unicode was invented. A Unicode character is 16 bits long and can therefore identify 65, characters within a language's alphabet. When browsing the Windows. The functions within this book cover only the ANSI functions.

However, the Unicode functions usually differ only in the type of string information passed to a function, and the text within this book should adequately describe the Unicode function's behavior. To achieve certain goals or solve specific problems, a developer may be forced to use lower-level Windows API functions that are simply not encapsulated by a Delphi object. It may also be necessary to extend the functionality of a Delphi object, and if this object encapsulates some part of the Windows API, it will be the API that the developer will likely have to use to extend the functionality by any great amount.

Indeed, there are literally hundreds of APIs out there that dramatically extend Windows' functionality, and due to the sheer numbers of API functions and the ever changing, ever expanding functionality being introduced by Microsoft, it would be nearly impossible to actively import every last function from every available API. Therefore, it is important that the well-prepared and capable Delphi programmer is familiar with hardcore Windows programming, as it is highly likely that you'll be called upon sometime in your Delphi career to make use of some Windows API functionality that is not encapsulated by the VCL.

There may even be situations where it is impractical to use the Delphi components that encapsulate Windows functionality. Delphi application as small as 10 KB. Every situation is different, and fortunately, as Delphi programmers, we have a lot of flexibility in this area.

Using direct Windows API calls may not always be necessary, but when it is, it's good to know that we have that option available to us.