How to verify some macro is available for a specific version of GLIBC that is installed on my PC?

How to verify some macro is available for a specific version of GLIBC that is installed on my PC?

[孙世龙 sunshilong]

Hi, list

How can I verify some macro is available for a specific version of
GLIBC that is installed on my PC, e.g:__MALLOC_HOOK_VOLATILE?

I would be grateful to have some help with this question.

Best regards.
Sunshilong

Re: How to verify some macro is available for a specific version of GLIBC that is installed on my PC?

[Florian Weimer]

* 孙世龙 sunshilong via Libc-help:

> How can I verify some macro is available for a specific version of
> GLIBC that is installed on my PC, e.g:__MALLOC_HOOK_VOLATILE?

You can read the glibc source code.

__MALLOC_HOOK_VOLATILE is an internal macro and should only be used
within glibc itself.  It can go away at any time.

Re: How to verify some macro is available for a specific version of GLIBC that is installed on my PC?

[孙世龙 sunshilong]

Thank you for your clarification.

>You can read the glibc source code.
No other methods? Maybe it's meaningful(or faster) when verifying when
a specific macro is first introduced then reading each version source
code.

>__MALLOC_HOOK_VOLATILE is an internal macro and should only be used
>within glibc itself.  It can go away at any time.
Do you indicate that the said macro could not be found in the headers of GLIBC?

Best Regards
Sunshilong

On Sun, Aug 16, 2020 at 6:08 PM Florian Weimer <fw@deneb.enyo.de> wrote:
>
> * 孙世龙 sunshilong via Libc-help:
>
> > How can I verify some macro is available for a specific version of
> > GLIBC that is installed on my PC, e.g:__MALLOC_HOOK_VOLATILE?
>
> You can read the glibc source code.
>
> __MALLOC_HOOK_VOLATILE is an internal macro and should only be used
> within glibc itself.  It can go away at any time.

Re: How to verify some macro is available for a specific version of GLIBC that is installed on my PC?

[Florian Weimer]

* 孙世龙 sunshilong:

> Thank you for your clarification.
>
>>You can read the glibc source code.

> No other methods? Maybe it's meaningful(or faster) when verifying when
> a specific macro is first introduced then reading each version source
> code.

The Linux man-pages project provides this information in some special
cases.  But I do not know a source of this information for the general
case.

>
>>__MALLOC_HOOK_VOLATILE is an internal macro and should only be used
>>within glibc itself.  It can go away at any time.

> Do you indicate that the said macro could not be found in the
> headers of GLIBC?

Some of the headers contain internal implementation macros, identified
by two leading underscores (__).  Thet are not supposed to be used
outside of glibc, but are included in installed headers for technical
reasons.