In all these calls, the U32 wn parameters are warning category constants. You can see the ones currently available in "Category Hierarchy" in warnings, just capitalize all letters in the names and prefix them by WARN_. So, for example, the category void used in a perl program becomes WARN_VOID when used in XS code and passed to one of the calls below.
U32 wn
WARN_
void
WARN_VOID
Returns a boolean as to whether or not warnings are enabled for the warning category w. If the category is by default enabled even if not within the scope of use warnings, instead use the "ckWARN_d" macro.
w
use warnings
Like "ckWARN", but for use if and only if the warning category is by default enabled even if not within the scope of use warnings.
"ckWARN"
Like "ckWARN", but takes two warnings categories as input, and returns TRUE if either is enabled. If either category is by default enabled even if not within the scope of use warnings, instead use the "ckWARN2_d" macro. The categories must be completely independent, one may not be subclassed from the other.
Like "ckWARN2", but for use if and only if either warning category is by default enabled even if not within the scope of use warnings.
"ckWARN2"
Like "ckWARN2", but takes three warnings categories as input, and returns TRUE if any is enabled. If any of the categories is by default enabled even if not within the scope of use warnings, instead use the "ckWARN3_d" macro. The categories must be completely independent, one may not be subclassed from any other.
Like "ckWARN3", but for use if and only if any of the warning categories is by default enabled even if not within the scope of use warnings.
"ckWARN3"
Like "ckWARN3", but takes four warnings categories as input, and returns TRUE if any is enabled. If any of the categories is by default enabled even if not within the scope of use warnings, instead use the "ckWARN4_d" macro. The categories must be completely independent, one may not be subclassed from any other.
Like "ckWARN4", but for use if and only if any of the warning categories is by default enabled even if not within the scope of use warnings.
"ckWARN4"
To install less, copy and paste the appropriate command in to your terminal.
cpanm
cpanm less
CPAN shell
perl -MCPAN -e shell install less
For more information on module installation, please visit the detailed CPAN module installation guide.