What will happen if I write a file with StreamWriter to a full hard drive?

Question

I am writing many .csv files to my hard drive to log some measurement data using the StreamWriter and CsvHelper from Josh Close class:

using (TextWriter writer = new StreamWriter(path,true))
using (CsvWriter = new CsvWriter(writer))
{
    writer.WriteLine("1...");
    /// ...
    /// ...
    /// ...
    writer.Flush();
}

Overnight their can be up to 500 MB of data stored. So today this question bothers me: What will happen if my hard drive or USB drive has no more empty space and I want to write a new file? And what is a best practice to prevent this situation? Will this throw an exception or not? I found nothing in the .NET documents about this situation.

It will throw an exception and your answers are limited to "buy a bigger USB stick" or "write less data". — DavidG, Oct 16 '15 at 15:13
Simply archive the data if you dont need it, or simply use a compress method to save from the space. — Hozikimaru, Oct 16 '15 at 15:16
You can't make drive space appear just because you need it. If the drive is full, you can't write anymore. — Ron Beyer, Oct 16 '15 at 15:21
@DavidG Ok thank you, and which Exception? To you have an link for me? — Sebastian Richter, Oct 16 '15 at 15:23

score 1 · Accepted Answer · edited May 23 '17 at 12:14

1

It will throw a new IOException. You can check if the exception is disk full like this (disk full check taken from here)

try
{
    //Write stuff to disk
}
catch(IOException ex)
{
    if(IsDiskFull(ex))
    {
        //Disk is full
    }
}


public static bool IsDiskFull(Exception ex)
{
    const int ERROR_HANDLE_DISK_FULL = 0x27;
    const int ERROR_DISK_FULL = 0x70;

    int win32ErrorCode = Marshal.GetHRForException(ex) & 0xFFFF;
    return win32ErrorCode == ERROR_HANDLE_DISK_FULL || win32ErrorCode == ERROR_DISK_FULL;
}

edited May 23 '17 at 12:14

Community

1
1

answered Oct 16 '15 at 15:26

DavidG

113,891
12
217
223

1

I was about to link to that answer as well :) – user1666620 Oct 16 '15 at 15:27
@SebastianRichter Did this help then? – DavidG Oct 16 '15 at 15:46
@DavidG yes that will help me! I didn't find anything to my question. Maybe I googled wrong keywords. Also I don't know why my question go down voted? For me this was an important problem. – Sebastian Richter Oct 16 '15 at 16:03
That may be because of the comment you put about not accepting the "buy a bigger USB stick". Anyway, I removed that and tidied up the question. I'll give you an upvote now :) – DavidG Oct 16 '15 at 16:08
@DavidG Thank you. Maybe I should let the jokes, next time :). – Sebastian Richter Oct 16 '15 at 18:33

score 0 · Answer 2 · answered Oct 16 '15 at 15:16

You should keep separated rolling files, which older files can be deleted when your hard disk is becoming full (never wait for that to happen!).

Check remaining drive space vs. the data you need to write, and perform the deletion before you actually run out of space.

What will happen if I write a file with StreamWriter to a full hard drive?

2 Answers2