When I try to copy one instance of a class to another instance of the same class, the compiler has a hissy fit. It occurs when the object in the class is a bitfield and is volatile. One of the error messages I find humorous. It mentions a const volatile. I've never seen one of those before.
Here's a simple project. It consists of main.cpp only. I define the simple class, create 2 instances of it, and try to copy one to the other using the good old assignment operator '='. It only fails if I use gcc with the -std=gnu++11. It only fails if I declare the data member to be volatile and a bitfield.
I have seen this problem before, or something similar, with gcc. Motorola's compiler sees no problem.
Here is main.cpp and also the project template.
// This program copies one instance of a class to another instance of the same class.
// Gcc with -std=gnu++11 fails if the object in the class is a bitfield and is volatile.
// If I remove the -std=gnu++11 from the project, it compiles okay.
// Microsoft's compiler thinks it's okay too. This makes 3 of us. ;)
// I'm using Atmel Studio 6.2.
// I put -std=gnu++11 in the compiler options Miscellaneous category.
class Class_with_volatile {
struct Control {
unsigned char software : 1;
unsigned char reserved : 7;
};
// If you comment out the following volatile and uncomment the non-volatile, it compiles okay.
volatile Control control; // This doesn't work with gcc ++11.
// Control control; // This works.
};
int main(void)
{
Class_with_volatile class_with_volatile_1;
Class_with_volatile class_with_volatile_2;
class_with_volatile_2 = class_with_volatile_1; // Won't compile with -std=gnu++11 and volatile bitfield object.
while(1)
{
volatile int count;
count++;
}
}
