MultiByteToWideChar removed from unix exports

[gbalykov]

Could you, please, clarify, why dotnet/coreclr#22500 removed MultiByteToWideChar from unix exports (src/dlls/mscoree/mscorwks_unixexports.src)?

We use this function in Tizen application loader for string conversion. Is there another function to use instead?

cc @alpencolt @alexander-aksenov @jkotas

[jkotas]

These exports are meant to be used by System.Private.CoreLib only. We are removing them as CoreLib keeps using less of them.

Why do you need to convert strings to UTF16 in the Tizen application loader? Can you use the "Unix hosting APIs" that take UTF8 strings? https://github.com/dotnet/coreclr/blob/master/src/dlls/mscoree/mscorwks_unixexports.src#L2

[gbalykov]

We use MultiByteToWideChar to pass argument to SetEnvironmentVariableW, which sets environment variable just before the call to coreclr_execute_assembly. These are the only two functions we use, which are not from "Unix hosting API".

What should be the correct approach here?

[janvorli]

@gbalykov could you call linux setenv function before calling coreclr_initialize? The PAL initialization copies all the env variables from the system environment into its local data structures.

[jkotas]

Also, what is the environment that you are setting? Another option may be to pass the piece of data as key/value pair and fetching it using AppContext.GetData on the managed side.

[gbalykov]

@janvorli @jkotas

We need to setup XDG_DATA_HOME right before coreclr_execute_assembly.

We initialize CoreCLR before application is known, so, during call to coreclr_initialize, correct value of XDG_DATA_HOME is not yet known. Application becomes known only before coreclr_execute_assembly.

SetEnvironmentVariableW was also removed recently. What do you think about adding new Unix hosting API coreclr_set_environment_variable?

cc @alpencolt

[jkotas]

Would creating a delegate to Environment.SetEnvironmentVariable using coreclr_create_delegate and calling that to set the environment variable work?

[gbalykov]

Environment.SetEnvironmentVariable is overloaded and coreclr_create_delegate is not allowed to create delegate for overloaded methods, see: https://github.com/dotnet/coreclr/blob/84dc3732c6fd0f4739214eb83ffd643a33a5da17/src/vm/corhost.cpp#L865

What do you think about adding Environment.SetEnvVariable with the same signature as SetEnvironmentVariable?

public static void SetEnvVariable(string variable, string? value)

[jkotas]

Do you have any convenient assembly in your apps to put this wrapper into?

[gbalykov]

Yes, solution with delegate for wrapper, located in our Tizen specific lib, works, thank you!