I have some old linux code I'm trying to port to Windows. When I first built it as a straight native DLL, I go no issues with this piece of code, but when I tried making it a mixed-mode C++/CLI DLL, I got an unresolved external object error on this:
extern "C" char** environ;
Why would this work for native and not CLI? Any idea how to work around this, or what it even does?
That holds the environment variables (PATH, etc, etc). The C standard (if i recall correctly) requires environ to point to an array of these variables. They're also passed as the 3rd argument to the main entry point function.
Apparently, for some reason, the C++/CLI doesn't initialize that.
To fix that, you can allocate it yourself and fill with either either getenv (C) or Environment.GetEnvironmentVariables (Managed C++). I don't know of any in-place fix, but it shouldn't be too hard.
来源：https://stackoverflow.com/questions/2692855/extern-c-char-environ-windows-c-cli