Disable export of NimMain and NimDestroyGlobals

[ashe27]

Summary

For dynamic library projects, Nim enforces the export of the NimMain and NimDestroyGlobals functions. In my project, the exported functions have a unified naming convention and include their own initialization and unloading functions (MyInit, MyUninit). I would prefer to initialize within my own exported functions, but Nim does not provide me with this opportunity. Therefore, I have no choice but to proceed in the following way:

{.emit: """
# Forward declaration
N_LIB_EXPORT N_CDECL(void, NimMain)(void);
N_LIB_EXPORT N_CDECL(void, NimDestroyGlobals)(void);

# Proxy method
static void CallNimMain() { NimMain(); }
static void CallNimDestroyGlobals() { NimDestroyGlobals(); }
""".}

proc CallNimMain() {.importc, cdecl.}
proc CallNimDestroyGlobals() {.importc, cdecl.}

proc MyInit() {.exportc, dynlib.} =
  CallNimMain()
  # some code...

proc MyUninit() {.exportc, dynlib.} =
  # some code...
  CallNimDestroyGlobals()

Of course, I have seen such declarations in the community:

proc NimMain() {.cdecl, importc.}

However, it doesn't work in Nim 2.2.0. The generated C code doesn't have a forward declaration for NimMain.

Description

Give the choice of exports to the developers, and provide the opportunity to directly call NimMain and NimDestroyGlobals in the Nim code.

Alternatives

No response

Examples

No response

Backwards Compatibility

No response

Links

No response

[litlighilit]

I would prefer to initialize within my own exported functions, but Nim does not provide me with this opportunity.

Consider --nimMainPrefix:prefix?

doc:

--nimMainPrefix:prefix

use {prefix}NimMain instead of NimMain in the produced C/C++ code

(see https://nim-lang.org/docs/nimc.html)

[litlighilit]

And IIRC, NimDestoryGlobals is currently not documented.

So rename NimMain via --nimMainPrefix:prefix may be a better choice

[ringabout]

NimDestroyGlobals is documented in https://nim-lang.org/docs/backends.html