z505/godll

how to create windows golang DLL and load into C, or delphi, or freepascal

goDLL

Project to show people how to create MS Windows golang DLL, then load it into lazarus program, or a plain fpc command line program or another golang exe. This implies you can also use the DLL in plain C or C++ Visual Studio or GCC project. Should also be able to port this to bsd/linux/macOS

Current way of making a DLL:

• compile go code with regular go compiler and put that puts code into .a and .h files for you. These are just like C code that GCC can use, but stored in compiled .a and .h files
• then build a dll based on the dummy .c file (CGO) that just links the .a and .h files (go code) into a dll, using CGO (GCC automatically from go) to build the dll

Well known issues with Go DLL's:

• AFAIK you can only add one go dll to a program, and only once, as multiple go dlls in the same program will confluct each other's go runtime at this time
• Unloading a dll will crash program... But one go dll loaded, and kept loaded, works..
• This may improve in the future as golang repairs these issues if they can.
• A go runtime (which is included in all golang programs/code) is similar to a borland BPL or a .net runtime: multiple runtimes can be tricky/conflicting. It can even overwrite data if multiple runtimes exist, possibly even more tricky than a BPL. This again could be fixed in the future by golang authors if they work on dll's and unloading more in the future.
• regarding unix dll/so: I have not tested or read about it enough to know the details. This project is just a Microsoft Windows DLL project example, could also work on unix
• Go DLL, not "God II"

Other ideas:

• Try statically linking go code into fpc, instead of dll put the code right into the exe directly using .a files, and making an fpc .h equivalent (should be easy)
• show its use also in a plain c program since not all people interested in go dll's are using fpc/lazarus
• try come up with solutions to fix "multiple go runtime" problems (multiple go DLLs loaded) and "unloading" (of dll) problems. See golang open issues 11100 and 11058
  • golang/go#11100
  • golang/go#11058