Delphi file io. I really don't recommend this approach.
I have already tried changing the Rewrite command to Write. Read formatted data from a file or text file. Quite likely it's the same process that this code lives in. ReadAllText(path) Console. If you add or remove a file to or from a project using the Projects Window, RAD Studio adds or removes this file to or from the Deployment Manager automatically. ReadAllBytes returns a new byte array containing the file data. And that String has to be converted to whatever encoding is used for the file. Write The delphi help files suggest that you use the Pascal routines if you can. An example how this could look: filename := '\klienci\'+linia_klient[id]+'. When you use file. Input and System. 1 1 1 silver badge. Try something like this: Copy Method : Copies the specified file to a new location, optionally with a new name Jan 8, 2011 · The file access is slow for large files, regardless of which part of the file is being read. . Before an application begins executing, System. Delphi does not specify how thing should be serialized to/from file, So the information you give leaves us guessing. Notes Static methods are not methods of an object - they are simply class functions or procedures available at any time. 11k 4 4 gold badges 53 53 silver badges 163 163 bronze badges. I would also note that your code falls foul of what I refer to as the Delphi memory stream anti-pattern. In XE2, you may have to use System. Name CloseFile Procedure Syntax procedure CloseFile(var F: File); procedure CloseFile(var F: TextFile); Description Call CloseFile to close a file that was opened with Append, Reset, or Rewrite. 104 File not open for input Reported by Read, Readln, Eof, Eoln, SeekEof, or SeekEoln on a text file if the file is not open for input. My text file is going to have a lot Feb 2, 2023 · The preceding method writes a string to a file, then closes the file. Write. Description: Returns a FileStream object configured to suit the file Mode, Access and Share atributes required for the file specified in PathString. Jul 7, 2016 · The RTL supports several ways of working with files. assigning the file based on the fact it is Reads the contents of the file into a byte array. :-) If that doesn't solve it, you're missing some information in your quest The DeleteFile function deletes a file given by its file name FileName. 12. SysUtils because of new namespace rules. One last feature that I love, is that you can actually configure the product to take different actions with certain exceptions, while still capturing others normally. IO' not found. Board index » delphi » File IO Problems. dummzeuch. Do I have to download something to have the . 106. S. writeln(tf, sNewPassword); However, you should probably use a more modern mechanism to write a file. txt file) that reads the file line by line, edit the content and save it in the new file. Aug 4, 2012 · However, nowadays you should use TFileStream to access/create files and don't use the old style Pascal routines anymore. Open a text file to allow appending of text to the end: AssignFile: Assigns a file handle to a binary or text file: CloseFile: Closes an open file: File: Defines a typed or untyped file: ReWrite: Open a text or binary file for write access: TextFile: Declares a file type for storing lines of text FileStream(SafeFileHandle, FileAccess) Initializes a new instance of the FileStream class for the specified file handle, with the specified read/write permission. Oct 12, 2014 · The downside to this is that the entire Memo content has to be stored into a temporary String in memory before the file is then touched. File IO Problems. NET edition of the program as well. Source position: systemh. Feb 25, 2024 · There are several problems within your code I'd like to address: The Execute-Method of the Open/SaveDialog is a function returning a boolean value indicating success (a filename was selected or entered) or abortion of the dialog. Aug 13, 2022 · Return the current file position. These are low-level file access routines. We have used the GWIOPM to do what you are asking, but note that it will be ok for 32-bit versions of Windows up to W7 etc (as is the case for most 'free' drivers). DeviceType to dtWaveAudio and MediaPlayer1. Length : Int64 : Gets the length in bytes of the stream. Move Method : Moves the specified file to a new location, optionally with a new name Feb 5, 2012 · I personally would elect not to use Pascal IO here. Declaration. txt'; if not FileExists(filename) then // "Create a file with the given name. Indy seems the way to go but for some reason it doesn't work so far. File not open for input. pas, so for . The first form of Copy only accepts a source and destination paths. But on Delphi 11 it is reporting [dcc32 Fatal Error] F2613 Unit 'System. WebSockets and Socket. Move Method : Moves the specified file to a new location, optionally with a new name Use a TStreamWriter, which is automatically buffered, and can handle flushing its buffers to the TFileStream automatically. Apr 23, 2009 · I'm writing millions of large integers to file and ended up trying TaaWriteBufferFilter which Ryan linked to which reduced a 30sec save to file on Win XP Pro down to about 6 seconds! So I'd say if you're doing lots of small writes I'd say it's definately worth your time spending a few mins to see if wrapping your TFileStream with a buffered Jun 17, 2013 · I'm doing a bit of a file-format converting, and looking at some Delphi code I was able to get my hands on to decode the original format. Select those files that you do not want overwritten during deployment (Overwrite). Delphi file support Delphi provides a number of different file access mechanisms. <. 102. Change it to. e. Output is a write-only file associated with the operating system's standard output (typically, the display). txt;*. Improve this question. The file handle is guaranteed to be closed by this method, even if exceptions are raised. Also, they have a . You can avoid Aug 13, 2022 · Delphi's runtime library has a better way to do file I/O using streams. It merely sets up the given TextFile variable so that future file operations (like Reset or Rewrite) will know which file name to use. What Docs said: Creates or opens a file or I/O device. You say you want a text file, so you can take a bit of a shortcut in this case by using a TStringList, which has file IO built in. … - Selection from Delphi in a Nutshell [Book] Aug 31, 2013 · First is reading a directory and copy all of the files into a backup folder. Though you have the problem of what to do with the temp file, as well as cleaning it up in the event of a problem in your run. If any of the files are currently in use as being written to and/or open, then bypass that file. If you want your code to be able to read Unicode data then Pascal IO cannot help you. WriteLine(readText) End Sub End Class Remarks. System. I really don't recommend this approach. 136k 20 20 gold badges 360 360 silver badges 485 485 bronze badges. gitignore templates Oct 12, 2023 · AssignFile (prevent the use of the older Assign procedure) - Assign a name to a file; Append - Opens an existing file for appending data to end of file and editing it; BlockRead - Read data from an untyped file into memory; BlockWrite - Write data from memory to an untyped file; CloseFile (prevent the use of the older Close procedure) - Close Copy Method : Copies the specified file to a new location, optionally with a new name Apr 26, 2010 · When serialized to a file, you probably mean that this record is written in binary to the file and the next record is written after the first one starting at position sizeof( structure) etc etc. Feb 27, 2013 · delphi; file; file-io; restart; Share. So, it is a string that looks like '*. Incorrectly formatted input for Read. The creation date and time of the file specified by PathString is set to the DateAndTime value. The names will include the ". The following table lists the parameters expected by this method. AssignFile has not yet been called. Dec 30, 2016 · You need to develop a format. 105 File not open for output Jul 6, 2022 · I need to monitor real time if a new file is created on a folder. Use quotes if the name includes one or more spaces. io for Delphi. How to remove the file extension I've already know(or think that I can do like this): Description: The Create method should really have been named CreateFile so as to distinguish from the Create constructor (as is the case in DirectoryInfo. How to work with text files and streams? Generally, Text files provide a simple, convenient, and permanent way of storing textual data. However, I want to pass multiple file types. I don't see where my mistake is. File. > The function returns a handle that can be used to access the file or device for various types of I/O depending on the file or device and the flags and attributes specified. Make sure it ends with a backslash (IncludeTrailingPathDelimiter) and then append your "Files" directory. Jan 9, 2013 · function AssignFile(var F: File; FileName: String; [CodePage: Word]): Integer; overload; Write() and Writeln() both have overloads that support UnicodeString and WideChar inputs. Aug 1, 2011 · In addition to the excellent suggestions above, check out this delphi code for writing and reading I/O. Refactored types and constants, as well as allow header injection before starting the WebSocket connection. Community Bot. Approaches to File I/O; Using File Streams; Manipulating Files. . tshepang. Aug 30, 2013 · I honestly couldn't imagine using Delphi without it. Read. Open a file for writing, erasing the previous contents. Mar 26, 2019 · Your call to writeln is not providing a file object, and so attempts to write to the standard output, which presumably does not exist in your process. FileSystemWatcher seems a perfect solution. " Jan 2, 2014 · Do a while loop (until the end of my *. Also, this may fail if the file is open by another application exclusively. Exactly what the format is doesn't matter, as long as it's consistent and preserves all of the data that you require to reconstruct the object. You're actually opening the file, moving the file pointer to the end of the file to get the size, and then closing the file. Delphi Developer. It creates the file whose name was specified in the PathString value, returning a FileStream object allowing access to the file. Again, if any of the files are currently in use as being written to and/or open, then bypass that file. Apr 29, 2021 · Note that I have avoided the need to check for a zero length file, and used Pointer(Bytes) so that the code will work when range checking is active. The only time not to use streams is when you cannot use the library and must stick to the Delphi Pascal language only. You can do what you describe using a string list to load the file and then SplitString from the StrUtils unit to parse the string. For example: Mar 2, 2009 · I can only advise you to use the more "modern" facilities for dealing with files. Return the size of a file, in records. Ken Kyler. Jan 10, 2023 · The standard file variable System. I'm developing a program that needs to parse the file name into a TTextField. You can obviously "clear" a file created with Notepad using Delphi, using a dozen different ways (including automating opening the file again with Notepad, selecting all the text, deleting it, and then saving the file with Notepad). If you're opening the file using the old style File, it's much different than if you're opening it with a modern TFileStream. Nov 27, 2012 · You can declare a variable of type File and use AssignFile, BlockRead, etc. Files transferred the old-fashioned way tend to pile up and be forgotten about, eventually costing you money in data storage fees. That can waste a lot of memory (albeit temporarily) and run slowly if the Memo has a lot of text in it. Follow edited Feb 27, 2013 at 7:55. In this talk, we will take a deeper look at text files and the algorithms used to read and write from text files or stream. Mar 16, 2020 · Delphi actually provides a component specifically for this task in TOpenTextFileDialog, but it can utilize the old pre-Vista file dialog. Aug 25, 2014 · Then rename the file (RenameFile)to a different name. In addition to input/output operations, you may want to manipulate Dec 3, 2009 · delphi; file-io; file-locking; Share. Seek. They are essentially the equivalent mechanism of C++'s IO streams library, which is, of course, the preferred way of doing file IO in C++. io, you avoid storing the file you’re sending in your cloud storage or mail server. 3k 24 24 gold badges 95 95 silver badges 138 138 Apr 30, 2013 · Well, clearly something else has locked the file. " Gets the operating system file handle for the file that the current FileStream object encapsulates. IO. to read from the file. The default file name extension is . The second form of Copy accepts an optional Overwrite parameter. Jul 7, 2016 · When using objects and routines that work with files, the best practice is to be attentive to the case of file names. Make sure you maintain an exclusive handle on the files the whole time they are on the disk too, or they can just be copied before they are deleted. Occasionally the read over the network takes a very long time (like 20 secs) and the app freezes, as the read is done from an idle handler in the main thread. These have the following values : Copy Method : Copies the specified file to a new location, optionally with a new name To remove the EXE file name from that string, so you have just the directory portion, call ExtractFilePath. These routines map to the Windows API functions and return file handles, not normal Pascal file variables. May 20, 2022 · So, you should be able to write an IO callback function with a custom file extension (for example, . I get those types from a FilterComboBox. Description: The Create method should really have been named CreateFile so as to distinguish from the Create constructor (as is the case in DirectoryInfo. pas files, only the name is required. Now includes SSL, a demo echo client, and echo server. Dec 13, 2003 · We have a real time system written in Delphi and running under Windows 2000 Advanced Server. asked Oct 5, 2018 · You could use CreateFile function to test file for accessing from your thread. The ">s" converts that to a string, again "as-is" May 26, 2020 · Delete files from the deployment list (click ). txt' ) ; if MyFile = INVALID_HANDLE_VALUE then raise Exception . Description: The MkDir procedure makes a new directory in the current directory. Given a string and a file path, this method opens the specified file, appends the string to the end of the file, and then closes the file. Both file streams and the global routines for reading from and writing to files are described in Approaches to file I/O . FileStream(String, FileMode, FileSystemRights, FileShare, Int32, FileOptions, FileSecurity) Jan 15, 2009 · Yes I want to read a simple a logfile into a TStringList and that is easy done with LoadFromFile. Jun 15, 2012 · Not in XE2. Read a line of data from a text file. Second is to move the file to another directory. It's easy for you to see that the code in the question works fine. Pieter van Wyk Pieter van Wyk. 105. Name : String : Gets the name of the FileStream that was passed to the Aug 21, 2011 · I have a Delphi 2006 app that writes to a file and then regularly renames it to a sequenced name, and creates a new one, i. The oldest is in support of consoles, where the Read, ReadLn, Write and WriteLn routines have a syntax that omits the file name. CreateDirectory). Optionally, this list may be limited by the Filter string. Use FindFirst and FindNext to make a loop that looks at all the files. Apr 2, 2012 · If everyone else who has the file open has allowed writing to the file, then the intended writer can open the file for writing, write to the file, and close it. Rename a file. gitignore files for your project by selecting from 571 Operating System, IDE, and Programming Language . If the others haven't allowed writing to the file, then the intended writer won't be allowed to open the file in the first place, and there's nothing it can do about it. The program usually does not read the file sequentially. So, you can create a file that has its codepage set to CP_UTF8, and then Write/ln() will automatically convert Unicode strings to UTF-8 when writing them to the file. On the other hand, using file. RES for resource), and have that callback load the WAV resource and read its data, and then you would set MediaPlayer1. The "slurp" word will read the entire contents of the file into memory, as-is, and give a "buffer". (See this StackOverflow discussion on the differences between the older TOpenDialog and newer TFileOpenDialog. Follow asked Apr 10, 2009 at 8:28. Modern code and libraries almost invariably prefer the stream idiom and by doing the same yourself you'll make your code easier to fit with other libraries. Get a list of files. If the file was deleted OK, then True is returned, otherwise False is returned. 2,358 9 9 The DeleteFile function deletes a file given by its file name FileName. Of greater importance to modern applications, are disk file operations. AssignFile does not open any files. SysUtils is included by default usually, but I gave you the unit name in my answer. – Disillusioned Commented Jan 29, 2017 at 22:41 Apr 24, 2011 · file-io; delphi-7; Share. // Create a BinaryReader to allow the file to be read back MyFileReader := System. Rewrite. File not open for output. Change the file position. BinaryReader. It also allows you to choose to append to an existing file if you need to, set character encodings for Unicode support, and lets you set a different buffer size (the default is 1024 bytes, or 1K) in its various overloaded Create constructors. Jan 29, 2009 · 3) Put the file into the TRichEdit using LoadFromFile, when processing use SaveToFile to put it to a temp file, and then process against the temp file to get your final product. Output are automatically opened, as if the following statements were executed: AssignFile(Input, ''); Reset(Input); Jan 4, 2016 · File not open Reported by CloseFile, Read Write, Seek, Eof, FilePos, FileSize, Flush, BlockRead, or BlockWrite if the file is not open. Streams are object oriented and offer much more flexibility and power than traditional Pascal I/O. Return result of last file IO operation. See this simple example and this Sep 7, 2015 · First, your method of getting the file size is extremely slow, especially if you're going to be using this to list a lot of files. Remove the first CloseFile call — the one immediately after you use AssignFile. So just be careful of that. Deleting a File; Finding a File; Renaming a File; File Date-time Routines; Copying a File; Working with ini Files and the System Registry. doc'. If the destination path points to an already existing file, Copy raises an exception. Rename. Jul 8, 2010 · delphi; file-io; fixed-length-record; Share. I use this with some of the Indy exceptions that can be thrown: Aug 14, 2013 · The return type for FileCreate since Delphi 2010 has changed from an Integer type to THandle. The file is looked for in the current directory. Reset. Create(MyFileStream); // Declare our array to hold the returned data Oct 29, 2009 · GetFileSizeEx() avoids the nitty gritty of handling > 4GB file sizes and detecting valid results, but also requires a file HANDLE, rather than a name, and (as of Delphi 2009 at least, I haven't checked 2010) isn't declared for you in the VCL anywhere, you would have to provide your own import declaration. Chapter 5 presents all the file I/O procedures. Create useful . If a file with the given name exists, open the file in write mode. Follow edited May 23, 2017 at 10:24. Use of the non-native Pascal file variable handlers such as FileOpen is discouraged. It accesses files to process from a file server (also a Windows 2000 Jun 23, 2011 · It's been a long while since I have done any Delphi programming, but I remember that file IO were much better served using TStream suite of classes (TFileStream for file IO). FileName to a filename ending with the custom extension. io can actually save you money. ReadLn. The file is closed. (load line -> edit -> write | load -> edit -> write | load line -> edit -> write | ) I am pretty new with Delphi developing, and I have also read some pages about TStringLists. FileSize. The Write (and the WriteLine which, like Delphi's WriteLn, appends a line break after the Write) method is heavily overloaded, and you can Write numbers, booleans, and objects to the stream. Oct 4, 2012 · The mask used when matching file names (for example, "*. But the problem is that the file can be already opened by another program at the same time so an Jun 13, 2014 · How do I make Delphi write to a text file without erasing the file's previous contents? I already know how to add text but as soon as I try adding more it just replaces the previous text that was already in the file. Jul 26, 2013 · Yes, it matters. RRUZ. With no file name, IO (Input and Output) is routed to the console. var MyFile : THandle ; begin MyFile := FileCreate ( 'C:\temp\bla. If the directory already exists, an EInOutError exception is thrown. Using TRegistry Aug 13, 2013 · I understand that the easiest solution is to simply add the file path to the front of every file my 'app1' is opening (I tried it and yes, it does work correctly), however, there are in reality, hundreds of files this main application accesses through a similar method (be they txt, ini or dll's) i. Use Copy to make a copy of a file. inc line 1409 INI File Processing There are 2 basic ways to use TmcCustomFile_IO in an INI file component Make it a parameter Derive from it Locically, it makes more sense to derive this component from TMemIniFile and to make an FFile_IO property and manipulate it as necessary. Dec 30, 2013 · delphi; file-io; shfileoperation; Share. IOResult. asked Description: The GetFiles method returns an array of strings that hold the absolute paths of the files in the specified absolute or relative PathString directory. Description: The GetFiles method returns an array of strings that hold the absolute paths of the files in the specified absolute or relative PathString directory. 101. Dec 1, 2020 · Copies a file to a given path. I don't know whether there is a limit of open files using the Windows API, but I just tested and could easily open 1000 streams in parallel: Aug 17, 2007 · My problem now is to find out what other app is using a file which I create (using TFileStream) and close (using FreeAndNil) and then attempt to rename (and fail) all in the same procedure. Oct 5, 2022 · Since the text file has no formatting, it can be used by different programs. Finally delete the file using DeleteFile, which does not move the file to the recycle bin. Mon, 07 Dec 1998 03:00:00 GMT. Topics. I use a logging mechanism which for every log call opens the log file, writes the log text and time, flushes and then closes the log file. Follow edited Apr 24, 2011 at 18:27. Let's write some code: Read past end of file. Jun 16, 2024 · 8th. Nov 17, 2010 · I have an app written in Delphi 2006 that regularly reads from a disk file located elsewhere on a network (100Mb ethernet). Open, Options: Synchronous IO Non Jan 29, 2017 · And this answer accurately points out that Read is failing, because you haven't provided the method with a valid location to store the data read from the file. As I said, this is a progressive problem. 103. In addition to using file streams, there are several run-time library routines for performing file I/O. ) Delphi file support Delphi provides a number of different file access mechanisms. The order of the chunks is user driven and cannot be predicted. rtf;*. Don't remove all the CloseFile calls because you evidently wish to process the same file My teacher assigned me to create a simple project: Create a form, which the user has to complete and when he presses the submit button, then the program should write all the information in different Feb 11, 2010 · I have the following task: download a file using HTTPS and authentication. 104. Open a file for reading. You read the file into a memory stream, which is essentially a byte array. Use ReadAllBytes to read the contents of a binary file. Nov 7, 2022 · Like I said above, I'm simply reading one line from an assigned file TP. IsAsync : Boolean : Gets a value indicating whether the FileStream was opened asynchronously or synchronously. Dim readText As String = File. exe" matches all the executable files). I have tried to pass that string directly to GetFiles and it doesn't work. If it is obvious, just let me know. Follow edited Aug 23, 2014 at 22:29. Disk is full. Move method. pas unit? P. Mask. It's a binary file, and I have the function for how the information is written and read from this file, so most of the things are clear. Jul 4, 2011 · If the savetofile call is at the program end, and the program terminates abnormally, then this call probably won't execute. goporqogdacfrchkxsht