#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
struct DeferConversionStruct{
void **ptr;
DeferConversionStruct(void **in)
{ ptr = in; }
#define CreatePtrConversion(type) \
DeferConversionStruct(type **in) \
{ ptr = (void **)in; }
CreatePtrConversion(int)
CreatePtrConversion(float)
CreatePtrConversion(double)
};
struct DeferStruct{
void (*function_ptr)(void *);
void **data_ptr;
~DeferStruct()
{
assert(*data_ptr);
function_ptr(*data_ptr);
}
};
#define CONCAT_(a,b) a##b
#define CONCAT(a,b) CONCAT_(a,b)
#define DEFER(f_ptr_in, d_ptr_in) \
DeferStruct CONCAT(SomeRandomVariable,__COUNTER__) = { \
.function_ptr = (f_ptr_in), \
.data_ptr = DeferConversionStruct{d_ptr_in}.ptr \
}
int main() {
int *a = 0;
DEFER(&free, &a);
a = (int *)malloc(31);
return 0;
}
