Checking for amount of open files while running SystemVerilog testbench

Question

I am running a test to compare output data of the system to a set of golden data generated on a text file, but when the test runs to around 2000 frames +, I start getting an error where is says:

warning-Cannot open file
 file could not be opened. Too many open files.

I tried to look for a system task in SystemVerilog to see if there is a task that can show all currently open files while the test is running, but I can't seem to find one. Is there a way for this to be done?

Answer 1

I don't think the IEEE Std 1800-2017 offers any way to directly know how many files are currently open.

However, you could look at the integer value returned by $fopen to see the value of the last file descriptor which was opened. When I open many files, the value increments by one every time a new file is opened. I tried this on 2 simulators.

Keep in mind that there are 2 ways to call $fopen: multichannel descriptor and file descriptor. They return different values.

Perhaps your simulator has a proprietary way to check for the number of open files. Look through your documentation, or contact the vendor for support.

Answer 2

There is no way to do this in SystemVerilog. However, you can use /proc file system on Linux to get a list of all open files for a process (use simv pid here):

ls -la /proc/<pid>/fd

If you need to do this in simv, you would need to write a small DPI-function and do the above using getpid() and system() C-functions.

Please see also: https://unix.stackexchange.com/questions/333186/how-to-list-the-open-file-descriptors-and-the-files-they-refer-to-in-my-curren