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CHAPTER 6. TEMPLATES FOR FUNCTIONS WITH POINTER TO FUNCTION
6.2. FUNCTIONS WITH RETURN VALUE OF POINTER TO FUNCTION
ChVaList_t ap;
funcHandle handle_ch, handle_c;
Ch_VaStart(interp, ap, varg);
/* get and save the Ch function pointer */
handle_ch = Ch_VaArg(interp, ap, funcHandle);
ptfun1_1_chdl_funptr = (void *)handle_ch;
printf("\nin ptfun1_1_setHandle_chdl(), Ch function pointer is %p\n",
handle_ch);
/* replace the Ch function pointer with the C one */
if(handle_ch == NULL) { /* NULL pointer will not replaced */
handle_c = NULL;
}
else {
handle_c = (funcHandle)ptfun1_1_chdl_funarg;
}
printf("in ptfun1_1_setHandle_chdl(), \
the corresponding C function pointer is %p\n\n", handle_c);
ptfun1_1_setHandle(handle_c);
Ch_VaEnd(interp, ap);
}
EXPORTCH funcHandle ptfun1_1_getHandle_chdl(void *varg){
ChVaList_t ap;
funcHandle retval_c = NULL, retval_ch = NULL;
Ch_VaStart(interp, ap, varg);
retval_c = ptfun1_1_getHandle();
if(retval_c == ptfun1_1_chdl_funarg) { /* check the consistency */
retval_ch = (funcHandle)ptfun1_1_chdl_funptr;
}
printf("in ptfun1_1_getHandle_chdl(), \
the returned C function pointer %p\n", retval_c);
printf("in ptfun1_1_getHandle_chdl(), \
Ch function pointer to be returned is %p\n\n", retval_ch);
Ch_VaEnd(interp, ap);
return retval_ch;
}
/**** C functions to replace Ch callback functions ****/
static void ptfun1_1_chdl_funarg() {
Ch_CallFuncByAddr(interp, ptfun1_1_chdl_funptr, NULL);
}
Listing 5 — C functions to be handled (ptfun1 1.c)
#include <stdio.h>
#include "ptfun1_1_c.h"
/* keep function handles in c space */
funcHandle handle;
void ptfun1_1_setHandle(funcHandle funptr) {
printf("Call Ch function in C space : ");
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