Declare variable type void *

[farmerdoug]

If I declare a variable to be type void * how do I assign values to it (int, float, and char ) and how do I read the variable.

Thanks

[sicarie]

You cannot declare variables of type void

[weaknessforcats]

void means no type. A void* describes a pointer variable that points to no type. That is, it is just an address.

You should be able to assign the address of any type to void* but you shoule get errors assgining the address in a void* to a pointer to a real type unless you typecast.

In any case, you cannot assign the value of an int, float, etc to a void* since those types contain actual values and not addresses.

The above comment applies to C. In C++ you do not use void*. There are templates for that.

[farmerdoug]

More info: I have a function
int ffpky(fitsfile *fptr, int datatype, char *keyname, void *value,
char *comm, int *status);
The data type tells the routine what it's getting: int, float etc.
In the calling program which I'm pretty sure is in c: How do I get an int, float, or string into value.

thanks.

[farmerdoug]

Thanks. I think I got it.

void means no type. A void* describes a pointer variable that points to no type. That is, it is just an address.

You should be able to assign the address of any type to void* but you shoule get errors assgining the address in a void* to a pointer to a real type unless you typecast.

In any case, you cannot assign the value of an int, float, etc to a void* since those types contain actual values and not addresses.

The above comment applies to C. In C++ you do not use void*. There are templates for that.