filestream

I'm trying to use C++ to write an entry in a specific place in a file so basicly I have ofstream ofs("file.dat", ios::binary | ios::app); ofs.seekp(220, ios::beg); ofs.write((char *)&i, sizeof(i)); But no matter what I do it always write at the end of the file. I suppose this is related to iso::app because according to the documentation app (append) Set the stream's position indicator to the end of the stream before each output operation But if I use ate or nothing it always erases the content of the file. Any help would be great :) Yes, it's the ios::app that's causing this behaviour. Replace

I have the following code block which is giving me a headache. Logically it should work as I am using the filestream providing the lock within the using statement. When it gets to the line that creates the StreamWriter, it fails saying "the file is not writable". Now my program is a multithreaded application. Any thread could be trying to write to this file. I need the program to lock the file, read the contents, check the contents, then write back any changes. During that process, no other thread should be able to access that file. using (var fs = File.Open(fileLoc, FileMode.Open, FileAccess

I'm fairly new to python coming from C/C++, I was wondering how I would get my 'main.py' to reconize/use the imput given from a bash shell as: python main.py < text.txt (the file is in plain text) I would use argparse to create an option parser that accepts a file path and opens it. import argparse def main(): parser = argparse.ArgumentParser() parser.add_argument('infile', type='open') args = parser.parse_args() for line in args.infile: print line if __name__ == '__main__': main() If type='open' does not provide enough control, it can be replaced with argparse.FileType('o') which accepts

I have run into something curious. I have a decompiler that extracts information from a binary file. I am extracting a series of objects that I need to write separately to disk as binary files. These objects are graphic models compiled into a library. The objects have names embedded in them and I need to use that name as the file name. I am using : try { // Open file for reading . using (var fileStream = new FileStream(fileName, FileMode.Create, FileAccess.Write)) { // Writes a block of bytes to this stream using data from a byte array. . fileStream.Write(byteArray, 0, byteArray.Length); //

I have been asked to do the following in C#: /** * 1. Create a MultipartPostMethod * 2. Construct the web URL to connect to the SDP Server * 3. Add the filename to be attached as a parameter to the MultipartPostMethod with parameter name "filename" * 4. Execute the MultipartPostMethod * 5. Receive and process the response as required * / I have written some code that has no errors, however, the file is not attached. Can someone have a look at my C# code to see if I have written the code incorrectly? Here is my code: var client = new HttpClient(); const string weblinkUrl = "http://testserver

I'm saving an uploaded image using this code: using (var fileStream = File.Create(savePath)) { stream.CopyTo(fileStream); } When the image is saved to its destination folder, it's empty, 0 kb. What could possible be wrong here? I've checked the stream.Length before copying and its not empty. There is nothing wrong with your code. The fact you say "I've checked the stream.Length before copying and its not empty" makes me wonder about the stream position before copying. If you've already consumed the source stream once then although the stream isn't zero length, its position may be at the end of

One of the features of asynchronous programming in .NET is saving threads during long running operation execution. The FileStream class can be setup to allow asynchronous operations, that allows running (e.g.) a copy operation without virtually using any threads. To my surprise, I found that running asynchronous stream copy performs not only slower, but also uses more processing power than synchronous stream copy equivalent. Is there any benchmark tests were done to compare a synchronous vs asynchronous operation execution (file, network, etc.)? Does it really make sense to perform an