Thread: Writing Files with a Timestamp - Extras appearing

Hi Everyone,

Been a while since I've posted on here!

So, I'm working on some C code for a data acquisition system to read out PMTs. That part hasn't been too bad, but I'm having a weird issue with writing the data out to a file.

When I have a test case set up, I should write a 120 kB to a file that's timestamped with the time the program runs.

However, my problem is that when I write the file, it writes a number of files with a new seconds timestamp! Each one is 120kB! It's absolutely baffling to me.

Here's some code:

I find the timestamp this way:

Code:

time(&curr_time);
time_info = gmtime(&curr_time);

strftime(new_time, 80, "%a_%b_%d_%Hh_%Mm_%Ss", time_info);

When I sprintf this string into a filename and write it, it writes what seem to be 6 files (or more, depending on how many seconds the program runs.) which look like so:

test_prefix_Tue_Jan_24_18h_25m_18s_suffix.dat
test_prefix_Tue_Jan_24_18h_25m_19s_suffix.dat
test_prefix_Tue_Jan_24_18h_25m_20s_suffx.dat
test_prefix_Tue_Jan_24_18h_25m_21s_suffix.dat

Where the first file is the filename I actually created, opened, and wrote.

What's weird is that, if I drop the %S modifier in the format string, there is only one file written at that particular time. This file is then the correct one.

Moreover, what's more weird is that if I print out every single time I close a file, there's only one fclose and one fopen operation in my program.

This problem is totally baffling to me. I'm using Microsoft Visual Studio C++ (and associated compilers) to develop this code (even though it's in C) since I need to be making DLLs to link into a Labview program. Is this a windows development environment kind of thing? Is the nature of the memory assigned for the time object and string tripping me up here?

Thanks for any help!

Thanks for the input, but I walked away from the problem then came back, and then it was working perfectly.

I think that it was a buffer issue since I had developed it all in one session, and I've added a fair amount of fflush() commands now. If it starts acting weird again, and / or I figure out that it was due to a different reason, then I'll post and let you know!