Question

I have this method which supposed to get a buffer and write some content to a file:

void writeTasksToDevice()
{

TaskInfo *task;
unsigned int i = lastTaskWritten;

printf("writing elihsa\n");
outputFile.write(" Elisha2", 7);
//pthread_mutex_lock(&fileMutex);

for(; i < (*writingTasks).size(); i++)
{
    task = (*writingTasks).at(i);
    if(NULL == task)
    {
        printf("ERROR!!! in writeTasksToDevice - there's a null task in taskQueue. By "
                " design that should NEVER happen\n");
        exit(-1);

    }
    if(true == task->wasItWritten)
    {
        //continue;
    }
    else // we've found a task to write!
    {

        printf("trying to write buffer to file\n");
        printf("buffer = %s, length = %d\n", task->buffer, task->length);<====PRINT HERE IS OK< PRINTING WHAT IS WANTED
        outputFile.write(task->buffer, task->length); <===SHOULD WRITE HERE
        printf("done writing file\n");
    }

}

//pthread_mutex_unlock(&fileMutex);


// TODO: check if we should go to sleep and wait for new tasks
// and then go to sleep




}

the buffer content is:

task->buffer: elishaefla

task->length: 10

i opened the stream in another init function using:

outputFile.open(fileName, ios :: app);
if(NULL == outputFile)
{
    //print error;
    return -1;
}

but at the end, the file content is empty, nothing is being written.

any idea why?

Answer 1

You did not provide enough information to answer the question with certainty, but here are some of the issues you might be facing:

1. You did not flush the buffer of the ofstream

2. You did not close the file that you are trying to open later on (if I’m correct, outputFile is a global variable, so it is not closed automatically until the end of the program)