Modify C API to return warnings #5282
Description
The C API currently returns errors on failure, and tries to fast fail as much as possible.
There are situations where the C API could do a valid computation but want to return some sort of warning. Motivating examples for this is forced type conversion when we create graphs, or transposing the storage of the graph in order to run an algorithm. These are steps that the C API takes to provide clean functionality, but are more expensive steps (in memory and/or computation) that the user could potentially optimize away by doing operations in a different order.
Modify the C API to also be able to return warnings. A proposed approach:
- Add a new error code: CUGRAPH_SUCCESS_WITH_WARNING
- If code returns CUGRAPH_SUCCESS_WITH_WARNING then the error message would contain the warning message