MkKernel_Setup_libmkkernel_JV_API

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

Collaboration diagram for MkKernel_Setup_libmkkernel_JV_API:

Functions
JNIEXPORT void JNICALL	Java_jvmkkernel_MkKernel_Cleanup (JNIEnv *env, jclass class)
	Java: [static] Cleanup() → C-API cleanup jvmkkernel internal memory …
JNIEXPORT void JNICALL	Setup (JNIEnv *env, jclass class)
	Java: [static] Setup() → C-API setup jvmkkernel internal memory …
static native void	jvmkkernel.MkKernel.Cleanup ()
	Java: [static] Cleanup() → C-API cleanup jvmkkernel internal memory …
static void	jvmkkernel.MkKernel.Setup ()
	Java: [static] Setup() → C-API setup jvmkkernel internal memory …

Detailed Description

MkKernel PACKAGE - Setup und Cleanup the jvmkkernel …

Initializing a jvmkkernel 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 jvmkkernel 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 jvmkkernel 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 jvmkkernel library must be known when the thread starts. This is not a problem as long as the external jvmkkernel library is linked to the application. However, if dlopen is used to load the jvmkkernel library, the current restriction is that the new data type from the jvmkkernel 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();
}

Initializing a jvmkkernel 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 jvmkkernel 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 jvmkkernel 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 jvmkkernel library must be known when the thread starts. This is not a problem as long as the external jvmkkernel library is linked to the application. However, if dlopen is used to load the jvmkkernel library, the current restriction is that the new data type from the jvmkkernel 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

Cleanup()

static native void jvmkkernel.MkKernel.Cleanup ( )

static

Java: [static] Cleanup() → C-API
cleanup jvmkkernel internal memory …

Java_jvmkkernel_MkKernel_Cleanup()

JNIEXPORT void JNICALL Java_jvmkkernel_MkKernel_Cleanup	(	JNIEnv *	env,
		jclass	class )

Java: [static] Cleanup() → C-API
cleanup jvmkkernel internal memory …

Definition at line 220 of file LibMkKernel_jv.c.

                                                                                     {
  MkRtSetup_NULL;
  MkCleanupTmpl();
}

Setup() [1/2]

static void jvmkkernel.MkKernel.Setup ( )

static

Java: [static] Setup() → C-API
setup jvmkkernel internal memory …

Definition at line 263 of file MkKernel.java.

                              {
    SetupTmpl();
  }

Setup() [2/2]

JNIEXPORT void JNICALL Setup	(	JNIEnv *	env,
		jclass	class )

Java: [static] Setup() → C-API
setup jvmkkernel internal memory …

Definition at line 226 of file LibMkKernel_jv.c.

                                                         {
  MkRtSetup_NULL;
  MkSetupTmpl();
}