Fail to install Lablgtk3 on Windows (Diskuv)

[F-Loyer]

I have compiled Gtk with gvsbuild, copied it in C:\gtk, added C:\gtk\binin the PATH. Then the cairo2 package does install.

However, òpam install lablgtk3` fails :

# [...]
# (cd _build/default/src && C:\DiskuvOCaml\BuildTools\VC\Tools\MSVC\14.26.28801\bin\HostX64\x64\cl.exe -nologo -O2 -Gy- -MD -D_CRT_SECURE_NO_DEPRECATE -IC:/gtk/bin/../include/gtk-3.0 -IC:/gtk/bin/../include/pango-1.0 -IC:/gtk/bin/../include -IC:/gtk/bin/../include/glib-2.0 -IC:/gtk/bin/../lib/glib-2.0/include -IC:/gtk/bin/../include/harfbuzz -IC:/gtk/bin/../include/freetype2 -IC:/gtk/bin/../inc[...]
# cl : Ligne de commande error D8021 : argument numérique non valide '/Wno-deprecated-declarations'
# File "src/dune", line 29, characters 3-11:
# 29 |    ml_pango cairo_pango_stubs
#         ^^^^^^^^
# (cd _build/default/src && C:\DiskuvOCaml\BuildTools\VC\Tools\MSVC\14.26.28801\bin\HostX64\x64\cl.exe -nologo -O2 -Gy- -MD -D_CRT_SECURE_NO_DEPRECATE -IC:/gtk/bin/../include/gtk-3.0 -IC:/gtk/bin/../include/pango-1.0 -IC:/gtk/bin/../include -IC:/gtk/bin/../include/glib-2.0 -IC:/gtk/bin/../lib/glib-2.0/include -IC:/gtk/bin/../include/harfbuzz -IC:/gtk/bin/../include/freetype2 -IC:/gtk/bin/../inc[...]
# cl : Ligne de commande error D8021 : argument numérique non valide '/Wno-deprecated-declarations'
# File "src/dune", line 27, characters 3-11:
# 27 |    wrappers
#         ^^^^^^^^
# (cd _build/default/src && C:\DiskuvOCaml\BuildTools\VC\Tools\MSVC\14.26.28801\bin\HostX64\x64\cl.exe -nologo -O2 -Gy- -MD -D_CRT_SECURE_NO_DEPRECATE -IC:/gtk/bin/../include/gtk-3.0 -IC:/gtk/bin/../include/pango-1.0 -IC:/gtk/bin/../include -IC:/gtk/bin/../include/glib-2.0 -IC:/gtk/bin/../lib/glib-2.0/include -IC:/gtk/bin/../include/harfbuzz -IC:/gtk/bin/../include/freetype2 -IC:/gtk/bin/../inc[...]
# cl : Ligne de commande error D8021 : argument numérique non valide '/Wno-deprecated-declarations'

https://learn.microsoft.com/en-us/cpp/build/reference/compiler-option-warning-level?view=msvc-170 gives the diffferent /W options. They don't follow the gcc conventions. (src/dune, src-goocanvas2/dune and src-sourceview3/dune have this option)

[garrigue]

I'm sorry, you probably need to at least use gcc to install lablgtk3.
It's been a long time I have not tried to compile anything directly under windows...

[F-Loyer]

But the Microsoft compiler from Visual Studio is the compiler of the Diskuv distribution. I can’t change it for gcc without changing the Distribution.

And it seems to be the privileged distribution on Windows. (tier 2 according to https://ocaml.org/docs/ocaml-on-windows)

[tleedjarv]

I was testing the new opam system-msvc feature and discovered that lablgtk3 builds just fine with MSVC and appears to work correctly. This was the only fix I needed (I didn't build any of the other packages):

diff --git a/src/dune b/src/dune
index b712a7f7..c996707d 100644
--- a/src/dune
+++ b/src/dune
@@ -34,6 +34,6 @@
    ml_gtkmenu ml_gtkfile ml_gtktree ml_gtkpack
    ml_gtkstock ml_gtkrange ml_gtkassistant
  )
- (c_flags         (:include cflag-gtk+-3.0.sexp) (:include cflag-extraflags.sexp) -Wno-deprecated-declarations)
+ (c_flags         (:include cflag-gtk+-3.0.sexp) (:include cflag-extraflags.sexp))
  (c_library_flags (:include clink-gtk+-3.0.sexp))
  (libraries threads cairo2))