MkKernel_Setup_libmkkernel_PY_API

MkKernel PACKAGE - Setup und Cleanup the pymkkernel … More...

Collaboration diagram for MkKernel_Setup_libmkkernel_PY_API:

Functions
static OT_ProcRet	pymkkernel_MkKernel_Cleanup (OtClass_ARGS)
	Python: [static] Cleanup() → C-API cleanup pymkkernel internal memory …
static OT_ProcRet	pymkkernel_MkKernel_Setup (OtClass_ARGS)
	Python: [static] Setup() → C-API setup pymkkernel internal memory …

Detailed Description

MkKernel PACKAGE - Setup und Cleanup the pymkkernel …

Initializing a pymkkernel library depends on the Target-Programming-Language (TPL) and the specific nature of the Programming-Language-Micro-Kernel (PLMK).

In general it is required to call a Setup style funtion as FIRST command because of:

• In a static build the shared library constructor/destructor is NOT called
• In a shared build the order of library loading is target-language-specific
• Every executable who uses a meta-code-library (META-LIBRARY) (MkKernel, MqMsgque, LcConfig, ...) which provide a language-specific-type (always assume this) and also support static-build (no constructor is called like C, C++, ...) require a call to the meta-library-setup-function for type-initialization at startup.

If more than one META library is called only the toplevel Setup is required:

• example: The MkKernelSetup is not required if MqMsgqueSetup or LcConfigSetup is already used.

shared library detail

A new pymkkernel library is initialized with Setup and released again with Cleanup. Both functions are automatically called upon loading and unloading of the shared library.

Example: Definition (C) of the pymkkernel library startup functions

MK_EXTERN void MK_DECL MkSetup (void) __attribute__ ((constructor(200)));
MK_EXTERN void MK_DECL MkCleanup (void) __attribute__ ((destructor(200)));

In the Programming-Language-Micro-Kernel (PLMK), a type is defined for each thread, which means that the new pymkkernel library must be known when the thread starts. This is not a problem as long as the external pymkkernel library is linked to the application. However, if dlopen is used to load the pymkkernel library, the current restriction is that the new data type from the pymkkernel library has not been defined in all existing threads.

The point in time when a library is loaded depends heavily on the programming language used.

• A linked language such as C or C++ usually has all libraries initialised at startup.
• A compiled language such as Java and C# only load a library when a function of the library is used and not when the library is declared.
• A scripting language such as Tcl normally loads the library as soon as the declaration (package require myLib) is made, which happens fairly close to the start of the program but is not guaranteed.

‍To avoid all the problems call the Setup directly at the start of the main program.

Example: Start of the LcConfigServer application from the example/cs directory

• The problem with the LcConfigServer application is that the libmkkernel and libmqmsgque libraries are loaded very early, at startup, and the liblcconfig very late, only on request.

static void Main(string[] argv) {
 
  LcConfig.Setup();
 
  var srv = MqFactoryCT<LcConfigServer>.Add().New();
 
  try {
    srv.LinkCreate(argv);
    srv.ProcessEvent(MqWaitOnEventE.FOREVER);
  } catch (Exception e) {
    srv.ErrorCatch(e);
  }
  srv.Exit();
}

Function Documentation

pymkkernel_MkKernel_Cleanup()

static OT_ProcRet pymkkernel_MkKernel_Cleanup ( OtClass_ARGS )

static

Python: [static] Cleanup() → C-API
cleanup pymkkernel internal memory …

Definition at line 710 of file LibMkKernel_py.c.

                                                      {
  OT_SETUP_hdl_static;
  OT_SETUP_NOARG(Cleanup_doc);
  OT_CHECK_NOARGS;
  MkCleanupTmpl ();
  OT_retObj_SET_None;
  goto end;
  error:
  OT_retObj_SET_Error;
  end:
  OT_retObj_RETURN;
}

pymkkernel_MkKernel_Setup()

static OT_ProcRet pymkkernel_MkKernel_Setup ( OtClass_ARGS )

static

Python: [static] Setup() → C-API
setup pymkkernel internal memory …

Definition at line 724 of file LibMkKernel_py.c.

                                                    {
  OT_SETUP_hdl_static;
  OT_SETUP_NOARG(Setup_doc);
  OT_CHECK_NOARGS;
  MkSetupTmpl ();
  OT_retObj_SET_None;
  goto end;
  error:
  OT_retObj_SET_Error;
  end:
  OT_retObj_RETURN;
}