How to solve NIOS and C++ problem with alt_remap_uncached

Altera_Forum · ‎11-18-2013

I'm using NIOSII eds for an app in my SOC. I'd like to use C++, but I'm having problems even getting it started.

What am I missing here?

extern "C" {# include <stdio.h># include "system.h"# include "adxl.h"

}

int main()

{ unsigned char *padxl = (unsigned char*)alt_remap_uncached((void*)(ADXL_BASE),sizeof(unsigned char));

printf("Hello from Nios II!!!!\r\n");

return 0;

}

gives me the following error:

'alt_remap_uncached' was not declared in this scope

Altera_Forum · ‎11-19-2013

Have a look at this document (http://www.altera.com/literature/hb/nios2/n2sw_nii52010.pdf) page 14-47. You need to include <sys/alt_cache.h>

Altera_Forum · ‎11-19-2013

Many thanks. That fixed it.

alt_remap_uncached must have been getting included somewhere else without the alt_cache.h in the .c version because it worked fine without it. It only presented a problem when I changed it to .cpp. But when I add the sys/alt_cache that made it all work.

Many thanks again.

Altera_Forum · ‎11-20-2013

In C it isn't necessary to have a function prototype in scope in order to call it, C++ does need one.

It is a good idea to enable a lot more of the C 'warnings' and to make them fatal by adding -Wall -Werror to the command line. Some of the warnings are a bit pedantic and can be turned off individually.