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[bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies.
From: |
Maxime Devos |
Subject: |
[bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies. |
Date: |
Fri, 08 Apr 2022 17:39:55 +0200 |
User-agent: |
Evolution 3.38.3-1 |
Olivier Dion schreef op vr 08-04-2022 om 10:28 [-0400]:
> and don't fully understand it.
lttn-ust probably has some header
/gnu/store/...-lttng-unst-VERSION/include/lttng.h or the like.
It would look something like:
[...]
#include <liburcu.h>
int lttng_foo(urcu_stuff *bar);
[..]
Then the 'patch-header-inclusion' phase detects the #include
<liburcu.h>, looks for include/liburcu.h in the package inputs, and
finds /gnu/store/...-liburcu-VERSION/include/liburcu.h. It then
replaces liburcu.h by /gnu/store/...-liburcu-VERSION/include/liburcu.h:
[...]
#include </gnu/store/.../include/liburcu.h>
int lttng_foo(urcu_stuff *bar);
[...]
Now, suppose I build an application dependning on lttng-ust. Then the
C compiler will ‘include’ 'lttng.h' in the {CROSS_,}C_INLUDE_PATH.
Then it sees:
#include </gnu/store/.../include/liburcu.h>
Now, as this is an absolute /gnu/store/... file name, the compiler
knows where to find it without looking into {CROSS_,}C_INCLUDE_PATH, so
it will find the header even though it might not be in
{CROSS_,}C_INCLUDE_PATH.
It's the same system as doing some 'substitute*' to bake in the
absolute file name of some executable into the compiled application to
avoid relying on PATH, except applied to C headers instead of
executables and {CROSS_,}C_CINCLUDE_PATH instead of PATH.
Greetings,
Maxime.
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- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Olivier Dion, 2022/04/07
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Maxime Devos, 2022/04/08
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Olivier Dion, 2022/04/08
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Olivier Dion, 2022/04/08
- [bug#54780] (C include header depropagation) Re: [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Maxime Devos, 2022/04/08
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies.,
Maxime Devos <=
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Olivier Dion, 2022/04/08
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Olivier Dion, 2022/04/08
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Maxime Devos, 2022/04/08
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Olivier Dion, 2022/04/08
- [bug#54780] [PATCH v2 1/2] guix: build: Add absolute-inclusions.scm., Olivier Dion, 2022/04/08
- [bug#54780] [PATCH v3 2/2] gnu: packages: Use absolute headers inclusion., Olivier Dion, 2022/04/21
- [bug#54780] [PATCH v3 1/2] guix: build: Add absolute-inclusions.scm., Olivier Dion, 2022/04/21
- [bug#54780] [PATCH v2 2/2] gnu: packages: Use absolute headers inclusion., Olivier Dion, 2022/04/08
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Maxime Devos, 2022/04/09
- [bug#54780] [PATCH] gnu: lttng-ust: Fix dependencies., Maxime Devos, 2022/04/09