444 warnings when building with MSVC

[sdegutis]

Things like this:

'=': conversion from 'int64_t' to 'int32_t', possible loss of data
'function': conversion from 'int64_t' to 'int32_t', possible loss of data
'function': conversion from 'int64_t' to 'double', possible loss of data
'+=': conversion from 'size_t' to 'int', possible loss of data
... 440 more

Dunno if it's a known thing or not.

[bnoordhuis]

They're harmless but you're not supposed to see them. How are you building quickjs? CMakeLists.txt has a bunch of /wdxxxx switches that disable them.

[sdegutis]

I don't know anything about CMake or have any clue how to use it, so I followed this vcpkg + cmake + vscode tutorial and downloaded quickjs-amalgam.zip and copied quickjs-amalgam.c and quickjs.h into my project and renamed the c file to quickjs.c and added quickjs.c to the executable in the cmakefile line that also adds main.c and then I opened the whole thing up in VS Code and hit CMake Run Without Debugging and then it built it all and ran it but VS Code shows the 444 errors in the Problems tab at all times, and when I open quickjs.c in VS Code directly, it adds a ton of errors saying things like function isn't expected here etc. But when I close that file those go away. I have no clue what I'm doing but I got SDL3 + quickjs working with a hello world so that's pretty fun.

[bnoordhuis]

You can copy the /wd flags from here to disable the warnings:

quickjs/CMakeLists.txt

Lines 67 to 83 in f0849ad

	xcheck_add_c_compiler_flag(/wd4018) # -Wno-sign-conversion
	xcheck_add_c_compiler_flag(/wd4061) # -Wno-implicit-fallthrough
	xcheck_add_c_compiler_flag(/wd4100) # -Wno-unused-parameter
	xcheck_add_c_compiler_flag(/wd4200) # -Wno-zero-length-array
	xcheck_add_c_compiler_flag(/wd4242) # -Wno-shorten-64-to-32
	xcheck_add_c_compiler_flag(/wd4244) # -Wno-shorten-64-to-32
	xcheck_add_c_compiler_flag(/wd4245) # -Wno-sign-compare
	xcheck_add_c_compiler_flag(/wd4267) # -Wno-shorten-64-to-32
	xcheck_add_c_compiler_flag(/wd4388) # -Wno-sign-compare
	xcheck_add_c_compiler_flag(/wd4389) # -Wno-sign-compare
	xcheck_add_c_compiler_flag(/wd4456) # Hides previous local declaration
	xcheck_add_c_compiler_flag(/wd4457) # Hides function parameter
	xcheck_add_c_compiler_flag(/wd4710) # Function not inlined
	xcheck_add_c_compiler_flag(/wd4711) # Function was inlined
	xcheck_add_c_compiler_flag(/wd4820) # Padding added after construct
	xcheck_add_c_compiler_flag(/wd4996) # -Wdeprecated-declarations
	xcheck_add_c_compiler_flag(/wd5045) # Compiler will insert Spectre mitigation for memory load if /Qspectre switch specified

msvc is a bit more pedantic in its default configuration than gcc or clang. I assume that answers your question so I'll go ahead and close this.

[chqrlie]

Instead of adding the flags to the CMake thing, we should use #pragmas for gcc, clang and msvc so these warnings are squelched in a more portable and resilient way :)

[sdegutis]

I assume these warnings wouldn't be here if I could vendor it via cmake anyway, right?

I'm trying to learn how to vendor projects in cmake. It seems like FetchContent might work, but it sounds like it's not meant for that.

It would be really nice if quickjs were in vcpkg.

[bnoordhuis]

@sdegutis does a patch like the one below help?

diff --git a/quickjs.c b/quickjs.c
index 8b9a3b5..fe30652 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -43,6 +43,10 @@
 #include <fenv.h>
 #include <math.h>
 
+#ifdef _MSC_VER
+#pragma warning(disable: 4018 4061 4100 4200 4242 4244 4245 4267 4388 4389 4456 4457 4710 4711 4820 4996 5045)
+#endif
+
 #include "cutils.h"
 #include "list.h"
 #include "quickjs.h"

[sdegutis]

@bnoordhuis I don't have this in my project anymore so I can't easily test it, sorry.