Topic: Why Visual C++ 2017 (VC15) still sports the v.14 number?

[Zane_TLI]

I'm testing the VC15 release, so I installed Visual C++ 2017 that's supposed to be "VC15".

But when I run the installed, I get this:

http://turbolab.it/immagini/med/come-installare-apache-windows-10-trasformare-pc-server-web-guida-definitiva-8978.img

As you can see, the package is 14.10.xx. I was expecting 15.yy.zz.

Moreover: if I try to run Apache VC15 without Visual C++ 2017 (VC15), I still get an error about VCRUNTIME140.dll (note the "14", I was expecting 15).

What's the deal here?

Thanks!

[admin]

That is correct, MS has numbered it 14.1 and not 15 because of the backward compatibility with VC14.

It numbering is also discussed here https://www.apachelounge.com/viewtopic.php?t=7612

[Zane_TLI]

Thanks for the link. I get that the Versioning situation is a bit messy.

Being VC15 actually 14.1, does it mean that it supersedes VC14 (2015) and the new version is OK for program built with VS2015 too? If so: VC14 is basically deprecated?

[admin]

In principal we could drop VC14, with php as module as example:

vc15 is backward compatible to vc14. That means, a vc14 module can sure be used inside vc15 binary. Thus, same for Apache and PHP as module. Regarding OpenSSL - the applink technology I introduced back then is in first place about staying compatible with different CRT. Even if it is promised to provide also compatibility between different versions, we've seen that it's not always true, recall the case where OpenSSL broke ABI by disabling weak ciphers.

Thus - in general dropping is OK, as long as the OpenSSL series matches, say both PHP and Apache are linked with either 1.0, or both with 1.1. For FCGI it of course doesn't matter, but for PHP as module. As httpd.exe provides the applink symbol, the PHP DLL will find it and possibly use incompatible routines. With this in mind, I wouldn't expect any issues if both bins are linked with same OpenSSL series. At apachelounge it is tested and no issues.

Planned:

VC11/14 only with OpenSSL 1.0.2
VC15 only with OpenSSL 1.1.0

This in line with the PHP-team policy, which we follow:

PHP 7.2 vc15 with OpenSSL 1.1.0
PHP 7.1 vc14 with Openssl 1.0.2
PHP 5.6 vc11 with OpenSSL 1.0.2

[Zane_TLI]

Great, thanks!

I also found this on the VC15 download page:

[Steffen]

Yep, we could drop VC14. But to be on the safe side we continue VC14.

I made the note clearer on the VC15 download page.

[Zane_TLI]

Thanks Steffen!

[Jan-E]

[Zane_TLI]

Jan-E: I was looking at the runtime library (the user-installable package), but thanks for reporting that it's not a clear-cut superseed while compiling!

[glsmith]

It's even less clear cut cause I have Jan's PHP 7.2.0a1 vc15 and my own Apache 2.4.26 vc15 build running on a server with only the VC14 redistributables on it and on the surface they seem to do just fine though I have rigorously tested either.

If you run printenv.pl in a VC15 command window you will find some new vars in it. Two of which are;

VISUALSTUDIOVERSION: 15.0
VSCMD_VER: 15.0.26430.13

So vc15 it is.