Normally, the compiler warns if a variable is declared but is never referenced. This attribute informs the compiler that you expect a variable to be unused and tells it not to issue a warning if it is not used.
This variable attribute is a GNU compiler extension.
Example:
void Variable_Attributes_unused_0()
{
static int aStatic =0;
int aUnused __attribute__((unused));
int bUnused;
aStatic++;
}
void unusedfunction() __attribute__((unused));