Re: building package: gcc 7.5.0 referenced instead of latest gcc; not sure why

[zimoun]

Hi Andy,

On Mon, 22 Feb 2021 at 16:10, Andy Tai <atai@atai.org> wrote:

> ./pre-inst-env gcc --version
> gcc (GCC) 10.2.0
> Copyright (C) 2020 Free Software Foundation, Inc.

Well, this GCC 10.2 is not used by the build-system…

> I tried to update a package definition (vtk) and then tried to build it
>
> ./pre-inst-env guix build -k -K vtk

…which instead uses 7.5.


> I am not sure why gcc 7.5 is being used;   no where in the package
> definition scm file references explicitly gcc 7.5.  I did not install
> gcc 7.5 explicitly either.

For example,

--8<---------------cut here---------------start------------->8---
$ guix environment vtk -C
[env]$ gcc --version
gcc (GCC) 7.5.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
--8<---------------cut here---------------end--------------->8---

Quickly said, the GCC comes from the cmake-build-system.

> (gcc 7.5 has problem compiling the package source so I want to make
> sure later gcc used)

It depends on what you want at the end: a variant for personal use or
for submitting.

For personal use, you can try:

  guix build -L /path/to/variant vtk --with-c-toolchain=gcc-toolchain@10

well, use package transformations, at CLI level or package level [1].

For submitting, I do not know what is the best.


Hope that helps,
simon

1: https://guix.gnu.org/manual/devel/en/guix.html#Defining-Package-Variants