add argument to rotating file sink for rotate_on_open

[pwm1234]

when true, the log file will be rotated when it is opened so the newly constructed file will start off being empty

[gabime]

I think a “truncate” param is what you want. like in basic_file_sink.

[pwm1234]

First, let me say THANK YOU for your work on spdlog and making it available!

Second, I did not know about the "truncate" param in basic_file_sink. But since truncate means to shorten or replace, which is different than "rotating," do you really want the argument to be named truncate? I am happy to do so, I just wanted to double-check.

Third, is this a pull request that you would accept once we iron out the details? If so, do you want me to make it using HEAD or am I okay at the 1.0 tag? (I chose this because that is the tag that vcpkg is using.) Also, I was unsure how to test this new functionality. I will add a test if you point me in the right direction.

[gabime]

First, let me say THANK YOU for your work on spdlog and making it available!

You're very welcome :)

Do you really want the argument to be named truncate?

I was referring to the actual implementation. It depends the purpose - if the purpose is is just starting with empty file, then maybe truncating is good enough.. If the purpose is to rotate first, and lose an old file, then "rotate_on_open" is fine.

Either way, the program is going to lose a log file..

If so, do you want me to make it using HEAD or am I okay at the 1.0 tag

Please use latest commit as the baseline for the PR.

[pwm1234]

I was referring to the actual implementation. It depends the purpose - if the purpose is is just starting with empty file, then maybe truncating is good enough.. If the purpose is to rotate first, and lose an old file, then "rotate_on_open" is fine.

Either way, the program is going to lose a log file..

Yes, the purpose and implementation is to rotate first. An old log file will be lost only if the maximum number has already been reached.

I will update the pull request to use the HEAD of the 1.x branch.

[pwm1234]

Just checking on this pull request. Is there something I can do to get this change merged?

[gabime]

@pwm1234 Please open a new pr. I see there are conflicts