ofstream doesn't flush

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ofstream error checking
ofstream::open
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c++ fstream read

I have the following code, running on Suse 10.1 / G++ 4.1.0, and it doesn't write to the file:

#include <fstream>
#include <iostream>

int main(){
    std::ofstream file("file.out");
    file << "Hello world";
}

The file is correctly created and opened, but is empty. If I change the code to:

#include <fstream>
#include <iostream>

int main(){
    std::ofstream file("file.out");
    file << "Hello world\n";
}

(add a \n to the text), it works. I also tried flushing the ofstream, but it didn't work.

Any suggestions?


If you check your file doing a cat , it may be your shell that is wrongly configured and does not print the line if there is no end of line. std::endl adds a \n and flush.

Ofstream is not making an output file - C++ Forum, I make a variable using std::ofstream and create a file, the file firstly does not i've tried it before, unfortunately it still doesn't make a text file :( Here it is, on a windows console application, ofstream is not creating any file at the given location, if I supply no-path, however, it does. No matter if I use the constructor or the open function, still doesn't work


The destructor should flush and close the file.

I am pretty sure, the error is an another place, either

1) You do not check at the right point in time. At which point do you compare the content of the file, "after" the exits, or do you set a breakpoint before the program exits and then you check the files content?

2) Somehow the program crashes before it exits?

ofstream - C++ Reference, typedef basic_ofstream<char> ofstream;. Output file stream. ios_base · ios · ostream; ofstream. Output stream class to operate on files. Objects of this class  Remember, the ifstream represents a stream of characters coming from an input file. We use ofstream to represent a stream of characers going to an output file. Both ifstream variables and ofstream variables use the open() function call to open a file. Each function call accepts a string argument that contains the path to the file to be opened.


Don't know if this is what you tried but you should do:

file << "Hello World" << std::flush;

Update; I'm leaving this answer here because of the useful comments

Based on feedback, I'll modify my advice: you shouldn't have to explicitly call std::flush (or file.close() for that matter), because the destructor does it for you.

Additionally, calling flush explicitly forces an I/O operation that may not be the most optimized way. Deferring to the underlying iostreams and operating system would be better.

Obviously the OP's issue was not related to calling or not calling std::flush, and was probably due to attempting to read the file before the file stream destructor was called.

[Solved] [C++] where does ofstream save?, When you open a stream to a file, you pass the location of the file (including the name) to that object. Typically, a name of the file is passed only  Have ofstream not create file if it does not exist? (c++) 5 posts I didn't see any flags for ofstream to do this, did I miss something or is there another way to do this?


Does

file << "Hello world" << std::endl;

work?

endl inserts a newline and flushes the buffer. Is that what you were referring to when you said that you'd already tried flushing it?

Issue with C++ ofstream: Doesn't create any file. No errors received , Issue with C++ ofstream: Doesn't create any file. No errors received. Normally, I would do GetLastError() to find out what might be wrong. But the reason I want to​  However whenever I make a variable using std::ofstream and create a file, the file firstly does not open and secondly does not appear in my directory. I am using Visual Studios 2013 to code and I started with an empty solution so there shouldn't have been any issues in regard to that.


You are working on Linux, which is a POSIX-compliant system. The POSIX standard defines what a line is:

A sequence of zero or more non-newline characters plus a terminating newline character.

So without the newline character, the file contains 0 lines and is therefore empty.

Trying to create a static ErrorLogger class but std::ofstream does not , Trying to create a static ErrorLogger class but std::ofstream does not write to the file. SOLVED. I have looked into this issue for ages, and have found out lots  (Of course, you’ll want to be sure to use a directory that doesn’t exist.) Then one of two things will happen: Either the directory and the file will get created, or nothing will happen. For example, on a Windows system, if we attempt to create a file in a directory that doesn’t exist, the system does not create the directory.


Reset a file with std::ofstream, I have a file opened with std::ofstream, and at one moment I want to clear it to empty, then write new contents into it. There is a method clear() but it doesn't do it​,  Pete C wrote: wiso wrote: >ok, but how I can use a fstream with io operation? I need to write to a file (I don't know if it exists, without rewrite it) and alse to read it.


c++, I created this function (as part of a larger program) a while back, but when I upgraded to Xcode 4, seemingly ofstream does not work anymore. For your first question, ofstream only creates a file because it does not depend on any information contained inside the file. All ofstream does is write to files, so if it creates a new, blank file, this doesn't interfere with writing information to it. An ifstream cannot create files, because an ifstream is supposed to be reading data.


Basics of File I/O, This library has classes ofstream ("output file stream") and ifstream ("input file For an input file, what if the file doesn't exist? doesn't have read permission?