Equivalent of `#pragma GCC diagnostic ignored "-Wunused-variable"` in nvc++

Accelerated Computing HPC Compilers nvc, nvc++ and nvfortran
1

I have a place, where I generate a variable on host which is unused, due to which I get a warning from nvc++ to the effect of variable "xyz" was declared but never referenced. I wonder if there is a pragma directive to supress that specific warning.

2

First use the “–display_error_number” to get the warning’s number, the use “–diag_suppress” to suppress it.

% nvc++ test.cpp --display_error_number
"test.cpp", line 5: warning #177-D: variable "j" was declared but never referenced
     int i,j;
           ^

% nvc++ test.cpp --diag_suppress177
%

See: HPC Compiler Reference Manual Version 22.7 for ARM, OpenPower, x86

Hope this helps,
Mat

3

Thank you for your reply. Is there something that only works locally with the specific line of code which I want to suppress rather than the complete TU?

4

I couldn’t find this in our documentation, so had to look at EDG’s docs (we use EDG’s front end C++), and found the “diag_supress” and “diag_warning” pragmas can be used to toggle a warning on or off.

For example here the unused warning is only emitted for the second use but not the first.

#include <stdio.h>
#include <stdlib.h>

#pragma diag_suppress 177
void foo () {
   int i,j;
   i = 1;
   printf("foo i=%d\n",i);
   return;
}
#pragma diag_warning 177
void bar() {
   int k,l;
   k = 1;
   printf("bar k=%d\n",k);
   return;
}
% nvc++ -c test.cpp
"test.cpp", line 13: warning: variable "l" was declared but never referenced
     int k,l;
           ^
5

This is wonderful. Thanks a lot for your help.