.msi install- can't find _internal/libs

[avbrummen]

meson setup buildir is unable to find \Meson\_internal\libs\python313.lib, however there is no 'libs' folder in '_internal' when I installed using the current .msi.
There is a python313.dll file within '_internal'.
Is this an error or is there some step I'm missing?

[eli-schwartz]

It's not really clear what you're trying to do in the first place. You haven't e.g. mentioned what project you are building.

If I had to take a wild guess you're trying to install a python module, but it's not clear why you'd try to do that using the MSI, rather than using meson installed via pip.

If that is what you're doing you'll have to instruct meson to build the python module against the specific python install you need. See the documentation on Machine Files. Note that a python build backend (pip compatible) such as meson-python would produce a machine file automatically.

[avbrummen]

So I'm currently trying to compile the source folder within NEMS (the national energy modeling system) on a Windows Machine.
NEMS authors direct users to use Meson build to compile all fortran scripts within this folder.
I downloaded meson build via the .msi because that seemed the most accessible to me given the Windows system.
My current steps are navigating within the source code folder on our machine and executing the meson.exe with 'setup builddir' which runs until it hits the error mentioned above:

' Could not find Python3 library 'C:\Program Files\Meson\_internal\libs\python313.lib'
Run-time dependency python found: NO (tried sysconfig)

meson.build:31:12: ERROR: Python dependency not found'

NEMS source folder that I'm trying to compile using Meson build: https://github.com/EIAgov/NEMS/tree/main/source

[eli-schwartz]

Thanks for the clarification. Looking at the project, they document that you need Python 3.11 and also to install the packages from https://github.com/EIAgov/NEMS/blob/main/requirements.txt into that python environment.

In the call trace from the meson files, I see:

• they search for a python dependency
• they use that python dependency to look up NumPy, a python numerical / data science package that also provides a C / Fortran API for other python packages
• they build some Fortran code into Python modules

I would recommend installing Meson at the same time as the other packages in that requirements.txt file, inside of a Python install. Don't use the MSI installer for Meson, as the MSI installer is primarily intended for use by people who wouldn't otherwise install Python and just need Meson to build C or C++ applications.

(Although the MSI does have an embedded python copy, it's not one you want to use to build python applications using.)

[avbrummen]

I just got it working!
Thank you so much for taking the time to walk me through this, I am very grateful!

[eli-schwartz]

Great, happy to help. :)

[avbrummen]

Unfortunately running into another error now, specifically:
"ERROR: Could not determine vs dep dependency prefix string. output: b'Microsoft (R) C/C++ Optimizing Compiler Version 19.16.27030.1 for x64\r\nCopyright (C) Microsoft Corporation. All rights reserved.\r\n\r\n' b"incdetect.c\r\nincdetect.c(1): fatal error C1083: Cannot open include file: 'stdio.h': No such file or directory\r\n"

I have 'stdio.h' downloaded from Windows SDK 10.0.17763.0, and the path is accessible. However, this seems to be a file needed for C compiling, and since NEMS is only compiling fortran I do not understand why this issue is popping up. See full meson-log from attempting to build the buildir attached.

meson-log.txt

[eli-schwartz]

NEMS is compiling a small amount of C code used for binding Fortran to NumPy. For example, fortranobject.c is distributed in source form as part of NumPy and needed internally. Also, typically what you'll find with Fortran code is that the vast majority of the logic is written in Fortran, but f2py or similar is used to generate a wrapper in C containing the Python API stub that intializes the Python module itself. The only purpose of that C code is to then immediately execute a Fortran function, sure, but still it needs a C compiler. :)

I'm not certain why it's falling to find stdio.h though.