mmap: Operation not permitted

[fpalma]

Hi to all,

I'm trying to convert a code that works, into a class.
This code maps the memory to manage the GPIO of the Raspberry Pi, and I can use it in a "normal" way, but If I convert the code into a class I get the error:

mmap: Operation not permitted
Failed to map the physical GPIO registers into the virtual memory space.

I attach the original code and the class. What can be the cause?
Thanks in advance!

[joan]

...
mmap: Operation not permitted
...

You need to run with permission to mmap /dev/mem.

The simplest way is to run the program with sudo.

[fpalma]

The simplest way is to run the program with sudo.

Yes, I run the program with sudo in both cases.

[StuartF]

You may be redefining the struct...

Code: Select all

class RpiMemory
{
	struct bcm2835_peripheral gpio;

maybe should be

Code: Select all

class RpiMemory
{
	bcm2835_peripheral gpio;

[fpalma]

maybe should be

Code: Select all

class RpiMemory
{
	bcm2835_peripheral gpio;

Thanks, it compiles, but happens the same error.

[jojopi]

Thanks, it compiles, but happens the same error.

No, that fixes it. At the time of the mmap, you just need the variable gpio that is in scope to be the one whose .addr_p you have actually initialized.

[StuartF]

Also you make the same redefinitions throughout the class.
I was hoping that the hint would of made you look through the whole code.

Once you have defined the struct, there is no need to use 'struct', just the name.

[fpalma]

OK, I have deleted "struct bcm2835_peripheral" from the constructor of the class, and now I can map the memory. Has been a basic mistake ...
Thanks a lot!