Change from char array to int array R/W nvram over spi

You're trying to do pointer arithmetic on a void pointer. You can't do that as the compiler cannot tell what type of data is pointing to.

Try this:

int *ptr;

ptr=(int *)Value;

Then replace all subsequent "Value" with "ptr".

Stefan

You're trying to do pointer arithmetic on a void pointer. You can't do that as the compiler cannot tell what type of data is pointing to.

Try this:

int *ptr;

ptr=(int *)Value;

Then replace all subsequent "Value" with "ptr".

Stefan

Or just change the precedence:

*(((int *)Value)+1)

or why not just change the function declaration to take a pointer to int?

Stefan

Thank you for your input.

These set and get functions must also work with types enum, char array, int. I cannot change the void.

"These set and get functions must also work with types enum, char array, int. I cannot change the void."

In that case you'll have to add a parameter to specify the type and perform the appropriate cast within the function. eg:

#define INT 1
#define FLOAT 2
etc

void Func(int type, void *ptr)
{
int *intptr;
float *floatptr;

switch(type)
{
case INT:
intptr=(int *)ptr;
//Do int specific stuff here
break;

case FLOAT:
floatptr=(float *)ptr;
//Do float specific stuff here
break;

//etc
}
}

Stefan

In C, adding "1" to a pointer does not increment the pointer to the next address (usually, adding a byte). It increments the pointer to point at the next whole object of the type pointed to, which may be several bytes wide. If you have an int* pi with value 0x1000, then (pi + 1) will be 0x1002, not 0x1001. (On Keil C, at least, sizeof(int) == 2. Other compilers will vary.)

You can't do arithmetic on void pointers because there is no type pointed to. "void" does not have size 1, or even size 0. so "void* pv; p = p + 1;" has no meaning. Sizeof what times 1?

If you are trying to manipulate generic objects of various types, then you will probably want to cast the void* to a U8*, and do all your arithmetic in bytes.

This design is headed for roll-your-own object-oriented programming. What you're really trying to do is implement a serialization method for each of a number of different objects.

I'd suggest making the variable ID list an enum, and using that enum as an index into a table of information about the variable (size and address). Then, the SPI functions can just be coded to send N bytes from address A, and use the values out of the table.

If the serialization methods become very different, or the objects get complicated, you might wind up with a table of function pointers to handle individual objects.

I notice the standards committee for the next round of C++ is discussing a typeof() operator. Maybe that will show up in C, as well.

Stefan,

This is the fix!

int *ptr;

ptr=(int *)Value;

Then replace all subsequent "Value" with "ptr".

Thank You

Mark