Search Results

Search found 12367 results on 495 pages for 'disk io'.

Page 92/495 | < Previous Page | 88 89 90 91 92 93 94 95 96 97 98 99  | Next Page >

• How do I open a file in such a way that if the file doesn't exist it will be created and opened automatically?

  - by snakile

  Here's how I open a file for writing+ : if( fopen_s( &f, fileName, "w+" ) !=0 ) { printf("Open file failed\n"); return; } fprintf_s(f, "content"); If the file doesn't exist the open operation fails. What's the right way to fopen if I want to create the file automatically if the file doesn't already exist? EDIT: If the file does exist, I would like fprintf to overwrite the file, not to append to it.

  Read the article

• Exciting new Evented I/O technologies

  - by Saif Bechan

  Lately I have been having my eye on evented I/O to tackle some of my web application problems. I have been looking at things as Python's Twisted, Ruby's Eventmachine, and Node.js. Are there any other alternatives to these three, maybe in other languages as PHP ?

  Read the article

• Python text file processing speed issues

  - by Anonymouslemming

  Hi all, I'm having a problem with processing a largeish file in Python. All I'm doing is f = gzip.open(pathToLog, 'r') for line in f: counter = counter + 1 if (counter % 1000000 == 0): print counter f.close This takes around 10m25s just to open the file, read the lines and increment this counter. In perl, dealing with the same file and doing quite a bit more (some regular expression stuff), the whole process takes around 1m17s. Perl Code: open(LOG, "/bin/zcat $logfile |") or die "Cannot read $logfile: $!\n"; while (<LOG>) { if (m/.*\[svc-\w+\].*login result: Successful\.$/) { $_ =~ s/some regex here/$1,$2,$3,$4/; push @an_array, $_ } } close LOG; Can anyone advise what I can do to make the Python solution run at a similar speed to the Perl solution? I've tried just uncompressing the file and dealing with it using open instead of gzip.open, but that made a very small difference to the overall time.

  Read the article

• How to create custom filenames in C?

  - by eSKay

  Please see this piece of code: #include<stdio.h> #include<string.h> #include<stdlib.h> int main() { int i = 0; FILE *fp; for(i = 0; i < 100; i++) { fp = fopen("/*what should go here??*/","w"); //I need to create files with names: file0.txt, file1.txt, file2.txt etc //i.e. file{i}.txt } }

  Read the article

• Could I return a FileStream as a generic interface to a file?

  - by Eric

  I'm writing a class interface that needs to return references to binary files. Typically I would provide a reference to a file as a file path. However, I'm considering storing some of the files (such as a small thumbnail) in a database directly rather then on a file system. In this case I don't want to add the extra step of reading the thumbnail out of the database onto the disc and then returning a path to the file for my program to read. I'd want to stream the image directly out of the database into my program and avoid writing anything to the disc unless the user explicit wants to save something. Would having my interface return a FileStreamor even a Imagemake sense? Then it would be up to the implementing class to determine if the source of the FileStream or Image is a file on a disc or binary data in a database. public interface MyInterface { string Thumbnail {get;} string Attachment {get;} } vs public interface MyInterface { Image Thumbnail {get;} FileStream Attachment {get;} }

  Read the article

• Seeking to a line in a file in g++

  - by Phenom

  Is there a way that I can seek to a certain line in a file to read or write data? Let's say I want to write some data starting on the 10th line in a text file. There might be some data already in the first few lines, or the file could even be empty. Is there a way I can seek directly to the line I want without having to worry about what's already in the file?

  Read the article

• [c++] How to create a std::ofstream to a temp file?

  - by dehmann

  Okay, mkstemp is the preferred way to create a temp file in POSIX. But it opens the file and returns an int, which is a file descriptor. From that I can only create a FILE*, but not an std::ofstream, which I would prefer in C++. (Apparently, on AIX and some other systems, you can create an std::ofstream from a file descriptor, but my compiler complains when I try that.) I know I could get a temp file name with tmpnam and then open my own ofstream with it, but that's apparently unsafe due to race conditions, and results in a compiler warning (g++ v3.4. on Linux): warning: the use of `tmpnam' is dangerous, better use `mkstemp' So, is there any portable way to create an std::ofstream to a temp file?

  Read the article

• Write to the second line of a PHP file

  - by Woz

  I have a php file that I want to add an include path to on the second line. I need to open the file and inset a line of code on line 2. I have tried a few techniques none of which are working but I think it has something to do with the text I am trying to write and possibly not escaping character correctly as I am not too familiar with file writing. So here is the file I want to write to: $file = $_SERVER['DOCUMENT_ROOT'].'/'.$domaindir.'/test.php'; Here is the piece of text I want to insert into the file: $dbfile = "include('".$_SERVER['DOCUMENT_ROOT']."/".$domaindir."/web_".$dbname.".inc.php');"; Then what I was doing was a string replace but all it did was bump the "session_start();" bit to a newline! Can anyone point me in the direction of a tutorial that might tell me how to insert this into the second line of my php file or indeed if anyone has any ideas? I can say for sure that the path to the PHP file is fully tested so i know its not that the file is not being open or written to. Any ideas would be much appreciated. Thanks in advance.

  Read the article

• File.Exists() returns false, but not in debug

  - by Tor Haugen

  I'm being completely confused here folks, My code throws an exception because File.Exists() returns false public override sealed TCargo ReadFile(string fileName) { if (!File.Exists(fileName)) { throw new ArgumentException("Provided file name does not exist", "fileName"); } Visual studio breaks at the throw statement, and I immediately check the value of File.Exists(fileName) in the immediate window. It returns true. When I drag the breakpoint back up to the if statement and execute it again, it throws again. fileName is an absolute path to a file. I'm not creating the file, nor writing to it (it's there all along). If I paste the path into the open dialog in Notepad, it reads the file without problems. The code is executing in a background worker. It's the only complicating factor I can think of. I am positive the file has not been opened already, either in the worker thread or elsewhere. What's going on here?

  Read the article

• How to get size of file in visual c++?

  - by karikari

  Below is my code. My problem is, my destination file always has a lot more strings than the originating file. Then, inside the for loop, instead of using i < sizeof more, I realized that I should use i < sizeof file2 . Now my problem is, how to get the size of file2? int i = 0; FILE *file2 = fopen(LOG_FILE_NAME,"r"); wfstream file3 (myfile, ios_base::out); // char more[1024]; char more[SIZE-OF-file2]; for(i = 0; i < SIZE-OF-file2 ; i++) { fgets(more, SIZE-OF-file2, file2); file3 << more; } fclose(file2); file3.close();

  Read the article

• I need to save a String to a text file using Java

  - by Justin White

  I am a beginner Java programmer. I am attempting to make a simple text editor. I have got the text from the text field into a variable that's a String, called "text". My question is, how can I save the contents of the "text" variable to a text file? Thank you!

  Read the article

• Reading a large text file to memory in C++

  - by NoneType

  Is there a way to read a large text file (~60MB) into memory at once (like a compiler flag to increase program memory limit) ? Currently, ofstream's open function throws a segmentation fault while trying to read this file. ifstream fis; fis.open("my_large_file.txt"); // Segfaults here The file just consists of rows of the form number_1<tabspace>number_2 i.e., two numbers separated by a tabspace.

  Read the article

• fopen() fails to open stream: permission denied, yet permissions should be valid

  - by about blank

  So, I have this error: Warning: fopen(/path/to/test-in.txt) [function.fopen]: failed to open stream: Permission denied Performing ls -l in the directory where test-in.txt is produces the following output: -rw-r--r-- 1 $USER $USER 1921 Sep 6 20:09 test-in.txt -rw-r--r-- 1 $USER $USER 0 Sep 6 20:08 test-out.txt In order to get past this, I decided to perform the following: chgrp -R www-data /path/to/php/webroot And then did: chmod g+rw /path/to/php/webroot Yet, I still get this error when I run my php5 script to open the file. Why is this happening? I've tried this using LAMP as well as cherokee through CGI, so it can't be this. Is there a solution of some sort? Edit I'll also add that I'm just developing via localhost right now. Update - PHP fopen() line $fullpath = $this->fileRoot . $this->fileInData['fileName']; $file_ptr = fopen( $fullpath, 'r+' ); I should also mention I'd like to stick with Cherokee if possible. What's this deal about setting file permissions for Apache/Cherokee?

  Read the article

• What would happen if a same file being read and appended at the same time(python programming)?

  - by Shane

  I'm writing a script using two separate thread one doing file reading operation and the other doing appending, both threads run fairly frequently. My question is, if one thread happens to read the file while the other is just in the middle of appending strings such as "This is a test" into this file, what would happen? I know if you are appending a smaller-than-buffer string, no matter how frequently you read the file in other threads, there would never be incomplete line such as "This i" appearing in your read file, I mean the os would either do: append "This is a test" - read info from the file; or: read info from the file - append "This is a test" to the file; and such would never happen: append "This i" - read info from the file - append "s a test". But if "This is a test" is big enough(assuming it's a bigger-than-buffer string), the os can't do appending job in one operation, so the appending job would be divided into two: first append "This i" to the file, then append "s a test", so in this kind of situation if I happen to read the file in the middle of the whole appending operation, would I get such result: append "This i" - read info from the file - append "s a test", which means I might read a file that includes an incomplete string?

  Read the article

• python open does not create file if it doesnt exist

  - by Toddeman

  I am using Python. What is the best way to open a file in rw if it exists, or if it does not, then create it and open it in rw? From what i read, file = open('myfile.dat', 'rw') should do this, no? it is not working for me (python 2.6.2) and im wondering if it is a version problem, or not supposed to work like that or what. The bottom line is, i just need a solution for the problem. I am curious about the other stuff, but all i need is a nice way to do the opening part. thanks in advance

  Read the article

• How can I determine if a file is read-only for my process on *nix?

  - by user109078

  Using the stat function, I can get the read/write permissions for: owner user other ...but this isn't what I want. I want to know the read/write permissions of a file for my process (i.e. the application I'm writing). The owner/user/other is only helpful if I know if my process is running as the owner/user/other of the file...so maybe that's the solution but I'm not sure of the steps to get there.

  Read the article

• C: Reading file with a starting point

  - by Shinka

  A simple question but I can't find the answer in my book. I want to read a binary file to seed a random number generator, but I don't want to seed my generator with the same seed each time I call the function, so I will need to keep a variable for my position in the file (not a problem) and I would need to know how to read a file starting a specific point in the file (no idea how). The code: void rng_init(RNG* rng) { // ... FILE *input = fopen("random.bin", "rb"); unsigned int seed[32]; fread(seed, sizeof(unsigned int), 32, input); // seed 'rng'... fclose(input); }

  Read the article

• Java: Inputting text from a file using split

  - by 00PS

  I am inputting an adjacency list for a graph. There are three columns of data (vertex, destination, edge) separated by a single space. Here is my implementation so far: FileStream in = new FileStream("input1.txt"); Scanner s = new Scanner(in); String buffer; String [] line = null; while (s.hasNext()) { buffer = s.nextLine(); line = buffer.split("\\s+"); g.add(line[0]); System.out.println("Added vertex " + line[0] + "."); g.addEdge(line[0], line[1], Integer.parseInt(line[2])); System.out.println("Added edge from " + line[0] + " to " + line[1] + " with a weight of " + Integer.parseInt(line[2]) + "."); } System.out.println("Size of graph = " + g.size()); Here is the output: Added vertex a. Added edge from a to b with a weight of 9. Exception in thread "main" java.lang.NullPointerException at structure5.GraphListDirected.addEdge(GraphListDirected.java:93) at Driver.main(Driver.java:28) I was under the impression that line = buffer.split("\\s+"); would return a 2 dimensional array of Strings to the variable line. It seemed to work the first time but not the second. Any thoughts? I would also like some feedback on my implementation of this problem. Is there a better way? Anything to help out a novice! :)

  Read the article

• accessing a file

  - by gcc

  How can I make sure that my program is the only one accessing a file?

  Read the article

• Split file with PHP and generate contents

  - by user201140

  How do I split the content below into separate files without the placeholder tags. I'd also like to take the text inside the placeholder tags and place them inside a new contents file. <div class='placeholder'>The First Chapter</div> This is some text. <div class='placeholder'>The Second Chapter</div> This is some more text. <div class='placeholder'>Last Chapter</div> The last chapter. Thanks.

  Read the article

• Writing Strings to files in python

  - by Leif Andersen

  I'm getting the following error when trying to write a string to a file in pythion: Traceback (most recent call last): File "export_off.py", line 264, in execute save_off(self.properties.path, context) File "export_off.py", line 244, in save_off primary.write(file) File "export_off.py", line 181, in write variable.write(file) File "export_off.py", line 118, in write file.write(self.value) TypeError: must be bytes or buffer, not str I basically have a string class, which contains a string: class _off_str(object): __slots__ = 'value' def __init__(self, val=""): self.value=val def get_size(self): return SZ_SHORT def write(self,file): file.write(self.value) def __str__(self): return str(self.value) Furthermore, I'm calling that class like this: def write(self, file): for variable in self.variables: variable.write(file) I have no idea what is going on. I've seen other python programs writing strings to files, so why can't this one? Thank you very much for your help.

  Read the article

• Reading files with Java

  - by sikas

  I would like to know how can I read a file byte by byte then perform some operation every n bytes. for example: Say I have a file of size = 50 bytes, I want to divide it into blocks each of n bytes. Then each block is sent to a function for some operations to be done on those bytes. The blocks are to be created during the read process and sent to the function when the block reaches n bytes so that I don`t use much memory for storing all blocks. I want the output of the function to be written/appended on a new file. This is what I've reached to read, yet I don't know it it is right: fc = new JFileChooser(); File f = fc.getSelectedFile(); FileInputStream in = new FileInputStream(f); byte[] b = new byte[16]; in.read(b); I haven't done anything yet for the write process.

  Read the article

• basic file input using C

  - by user1781966

  So im working on learning how to do file I/O, but the book I'm using is terrible at teaching how to receive input from a file. Below is is their example of how to receive input from a file, but it doesn't work. I have copied it word for word, and it should loop through a list of names until it reaches the end of the file( or so they say in the book), but it doesn't. In fact if I leave the while loop in there, it doesn't print anything. #include <stdio.h> #include <conio.h> int main() { char name[10]; FILE*pRead; pRead=fopen("test.txt", "r"); if (pRead==NULL) { printf("file cannot be opened"); }else printf("contents of test.txt"); fscanf(pRead,"%s",name); while(!feof(pRead)) { printf("%s\n",name); fscanf(pRead, "%s", name); } getch(); } Even online, every beginners tutorial I see does some variation of this, but I can't seem to get it to work even a little bit.

  Read the article

• Accessing a file (for writing) from a JBoss Web Service

  - by Andreas Grech

  Let's say I have this structure of my Java Web Application: TheProject -- [Web Pages] -- -- abc.txt -- -- index.jsp -- [Source Packages] -- -- [wservices] -- -- -- WS.java WS.java is my Web Service, which is situated in a wservices package. Now from this service, I need to access the abc.txt file and write to it. These are my urls: http://127.0.0.1:8080/TheProject/WS <- the webservice http://127.0.0.1:8080/TheProject/abc.txt <- the file I want to access To read the file, I tried with getResourceAsStream and I was successful in reading from it. But now I also want to write to this file, and I tried such a method but failed. Is there a way I can get access to the abc.txt file from WS.java and be able to successfully read from and write to it?

  Read the article

• Reading in data from a file into an array

  - by Sam

  If I have an options file along the lines of this: size = 4 data = 1100010100110010 And I have a 2d size * size array that I want to populate the values in data into, what's the best way of doing it? To clarify, for the example I have I'd want an array like this: int[4][4] array = {{1,1,0,0}, {0,1,0,1}, {0,0,1,1}, {0,0,1,0}}. (Not real code but you get the idea). Size can be really be any number though. I'm thinking I'd have to read in the size, maloc an array and then maybe read in a string full of data then loop through each char in the data, cast it to an int and stick it in the appropriate index? But I really have no idea how to go about it, have been searching for a while with no luck. Any help would be cool! :)

  Read the article

< Previous Page | 88 89 90 91 92 93 94 95 96 97 98 99  | Next Page >