Re: [musl] musl libc version

[Rich Felker <dalias@libc.org>]

On Wed, May 27, 2020 at 06:44:38PM +0300, Alexander Scherbatiy wrote:
> Hello,
> 
> Using glibc it is possible to get GNU C library version using
> confstr() function and _CS_GNU_LIBC_VERSION constant.
> 
> In musl the confstr() returns EINVAL for _CS_GNU_LIBC_VERSION.
> Is there a way to get libc version in musl?

Can you describe what you're trying to achieve with a version number?
musl specifically doesn't publish version numbers via macros or
runtime interfaces because they're a poor proxy for checking for the
particular feature/property/whatever you care about. For instance,
distros may backport the thing you want to an older version, and even
if not, you end up hard-coding knowledge about particular libcs that
quickly bitrots rather than making something robust and future-proof.

With that said, ability to test for some things is presently
inadequate, and there's a proposal I've made (based on previous
discussions with others) on libc-coord to improve this in a cross-libc
manner:

https://www.openwall.com/lists/libc-coord/2020/04/22/1

If you have input into what kinds of things you need to be able to
test for it would be very helpful.

Rich