Bug 19784 – DLL in BetterC mode - Symbol Undefined __acrtused_dll

When I try compiling a simple Windows DLL using DMD it works fine, but when I try doing it in BetterC mode I get "Error 42: Symbol Undefined __acrtused_dll". I guess the compiler generates calls to this function while compiling a DLL and this function is not defined in Cruntime, but rather defined in Druntime or Phobos. I think it should be possible to compile DLLs in BetterC mode, so this is a bug.

This seems to be specific to the DigitalMars C runtime, see https://digitalmars.com/ctg/acrtused.html. You may have more luck with -m32mscoff or -m64.

(In reply to kinke from comment #1) > This seems to be specific to the DigitalMars C runtime, see > https://digitalmars.com/ctg/acrtused.html. You may have more luck with > -m32mscoff or -m64. It doesn't compile with -m32mscoff or -m64 either: > dmd -of=dll.dll -betterC -m32mscoff dll.d lld-link.exe: error: subsystem must be defined Error: linker exited with status 1 > dmd -of=dll.dll -betterC -m64 dll.d lld-link.exe: error: subsystem must be defined Error: linker exited with status 1

This (linker) error can be gotten rid of with -L=/SUBSYSTEM:CONSOLE.

(In reply to kinke from comment #3) > This (linker) error can be gotten rid of with -L=/SUBSYSTEM:CONSOLE. I think the better thing to do is /DLL, but still I got these errors: > dmd -of=dll.dll -betterC -L=/DLL -m32mscoff dll.d lld-link.exe: error: <root>: undefined symbol: __DllMainCRTStartup@12 lld-link.exe: error: undefined symbol: _MessageBoxA@16 >>> referenced by dll.obj:(_Test@0) Error: linker exited with status 1 If I do /SUBSYSTEM:CONSOLE I get: > dmd -of=dll.dll -betterC -L=/SUBSYSTEM:CONSOLE -m32mscoff dll.d lld-link.exe: error: entry point must be defined Error: linker exited with status 1 If I add /ENTRY:DllMain to that I get: > dmd -of=dll.dll -betterC -L=/SUBSYSTEM:CONSOLE -L=/ENTRY:DllMain -m32mscoff dll.d lld-link.exe: error: undefined symbol: _MessageBoxA@16 >>> referenced by dll.obj:(_Test@0) Error: linker exited with status 1

__acrtused_dll is defined in snn.lib, which should be linked in for win32 DLL builds.

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