Thread: Accessing variables with memory address

I fail again. This time it's with C strings. Important code:

Code:

void *test_str = malloc(17);
*(int*)test_str = 3;
*(char*)((int*)test_str+1) = "Hello world!"; /* problem line */
test = (int)test_str;
printf("the value of test = %c, the type of test = %i\n\n", *(const char*)((int*)test+1), *((int*)test));

Error message on compile

error C2440: '=' : cannot convert from 'const char [13]' to 'char'

I can't seem to figure it out, any help?

Technically I'm assigning an array to a typeless block of memory. What I need is just a bulk memory copy function, would memccpy work or is there a better one?

It at least assigns the data now, I just can't print the whole string. New code:

Code:

memcpy((void*)((int*)test_str+1), "Hello world!", 13);
printf("the value of test = %s, the type of test = %i\n\n", /* this part kills the program */ *(const char*)((int*)test+1), *((int*)test));

As you can see by the comment it's in the print section. If I change the %s to a %c it prints "H". Any ideas how to get it to print the whole string?

Is there any particular reason you're making everything much harder than you need to?


Quzah.

Depends, do you have an easier method to implement dynamic typing? This will all be generated code anyway, I'm just trying to figure out how to get it to work.

Ahh, that's the problem. Works great now, many thanks. I shouldn't have any more problems now as arrays are work basically the same as these strings.

FYI, you are making code that is difficult to read even for experienced programmers.
First of all, such manipulation is often never good and I would avoid it if I could.
And secondly, try performing these operations in several steps to make readability easier.