Example: C DLL calling COBOL from Java

The example in Figure 1 shows the C interface DLL to use when calling COBOL.

Figure 1. Example: C interface DLL for calling COBOL from Java

/ c99  -o libc_to_cobol.so -Wc,exportall -Wl,                                 
dll -I/usr/lpp/java/J6.0.1/include                                              
    -I/usr/lpp/java/J6.0.1/include/zos c_to_cobol.c                             
                                                                              
#include <jni.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include "com_ibm_zos_batch_container_test_Java_Calls_Cobol.h"
                                                                               
void (*fetch(const char *name))();
typedef void cfunc();
                                                                                
JNIEXPORT jint JNICALL 
Java_com_ibm_zos_batch_container_test_Java_1Calls_1Cobol_CallCOBOL(JNIEnv * jenv, jobject jobj)
{
	cfunc *cobfetch_ptr;
	cobfetch_ptr = (cfunc *) fetch("XMPCOBJ3");    // loads fetched module
	if (cobfetch_ptr == NULL){
	    printf("\tfetch failed\n");
	}
	else
	{
	   printf("\tShould be going off to COBOL\n\n");
	   (*cobfetch_ptr)();         // sets up the proper linkage for the call
	}

	return(0);
}