Posted on pari-dev by Bill Daly : [edited to fit current filenames]
some additions by AVt for MSVC6 (using WinME) and pari 2.3.0 (and
I highly appreciate Karim's help to find it out - thx!)
=================================

Here is a description of the steps necessary to compile PARI with the MSVC
compiler under WIN32.

AVt: please note you need two extra file versions for mp.c and pariinl.h
which of course are due to Karim Belabas

1. Unzip the archive, preserving folder names so that the directory
structure is correct. I use WinZip to do this, and I put the files on my D:
drive, so that the files for pari-2.1.0 for example will be stored under
D:\pari-2.1.0. Note that the archive as downloaded, pari.tgz, is an archive
of an archive. Winzip doesn't know how to unzip pari.tgz, so I use Aladdin
Expander to do this, which will create for example the file pari-2.1.0.tar in
the same directory as pari.tgz. Unfortunately, Aladdin Expander doesn't know
how to unzip this file, so I use Winzip to do it. Isn't Windows wonderful?

1. AVt: one only needs files with extension *.c or *.h, so delete all the
others

2. MSVC doesn't like names of the form "pari-2.1.0", so rename the base
directory to something like "pari210". Now the files are stored under
D:\pari210.

2. AVt: in my example the name is pari_2_3_0

3. Start MSVC (I use version 6, but earlier versions will probably work the
same way).

4. Select "File\New..." and pick the "Project" tab to create a new project.
Select "Win32 Console Application" as the project type, and specify the
project name as "pari210". Make sure that the "Location" of the files is
D:\pari210. Click "OK", then select "An empty project" (should be the
default anyway) and click "Finish".

4. AVt: I just close MSVC and move the stuff to C:\temp\pari\pari_2_3_0
Then a double click on pari_2_3_0.dsw opens the project in that location.

5. Select "Project\Add to project\Files..." to add files to the project.
Select all the *.c and *.h files in src\basemath, src\headers,
src\kernel\ix86, src\language, src\modules and Odos, EXCEPT pariCE.[ch];
all of the files in src\gp except gp_rl.c; the files plotnull.c, plotport.c
and rect.h in src\graph.c; and the file src\kernel\none\mp.c.

5. AVt: you need some more files, 2 of them are separate:
add src/kernel/none/tune-gen.h
add src/kernel/none/mpinl.c
add src/kernel/none/level0.h

delete Odos/acro.c from project
delete src\kernel\ix86, one does not need that

replace Odos/pariinl.h by the accompanied version
replace /src/kernel/none/mp.c by the accompanied version

6. Select "Project\Settings" and pick the "C/C++" tab. Select
"Preprocessor" from the "Category" menu, and enter
"D:\pari210\src\headers,D:\pari210\Odos" into the "Additional include
directories" box. (I also select the "Code Generation" category and change
the "Struct member alignment" to "1 byte", but this may not be necessary.)
It is usually convenient for debugging to select the "Debug" tab and
specify a "Working directory", e.g. "D:\gp" if you have .gp files there
that you can use for testing.

6. AVt: C:\temp\pari\Odos,C:\temp\pari\src\headers are my settings
6. AVt: I do not change "Struct member alignment", leave it at default.

AVt:
The overall directory structure should look like this in C:\temp

  pari 
    |
    |---- Odos
    |---- pari_2_3_0
    |         |
    |         |---- debug
    |         |---- release
    |---- src
           |
           |
           ...

AVt: find an extra file listing to check it all ...

You should now be able to build and test the program. When you want to
build a release version, you will have to repeat step 6 above, since MSVC
doesn't apply the project settings globally.

AVt: in the release version you can disable language extensions to make
the exe a bit smaller

A couple of points:
-------------------
You may get some inconsequential warning messages. You can suppress these
by adding a line of the form:

   #pragma warning(disable: ...)

to paricfg.h, where ... is a space-delimited list of warning numbers, e.g.
"4018 4244" corresponding to the warnings C4018 and C4244.

When you compile a release version, global optimization is enabled by
default. MSVC is fairly buggy with global optimization, so you may find
that some modules won't compile with it, e.g. sumiter.c. You can either
disable global optimization (in "Project\Settings" under the tab "C/C++" in
the category "Optimization"), or you can surround the offending code with:

   #pragma optimization("g", off)
   ...
   #pragma optimization("g", on)


AVt: I just ignore the warnings about type conversions, they have no effect

AVt: I had no problems with optimization for version 2.3.0, overall it
compiles and links with "pari_2_3_0.exe - 0 error(s), 104 warning(s)"

AVt: the result has restricted functionally as command line application.
I played a bit with MS variants, but could not resolve this.