API¶
oneDNN has both C and C++ APIs available to users for convenience. There is almost a one-to-one correspondence as far as features are concerned, so users can choose based on language preference and switch back and forth in their projects if they desire. Most of the users choose C++ API though.
The differences are shown in the table below.
Features |
C API |
C++ API |
|---|---|---|
Minimal standard version |
C99 |
C++11 |
Functional coverage |
Full |
May require use of the C API |
Error handling |
Functions return status |
Functions throw exceptions |
Verbosity |
High |
Medium |
Implementation |
Completely inside the library |
Header-based thin wrapper around the C API |
Purpose |
Provide simple API and stable ABI to the library |
Improve usability |
Target audience |
Experienced users, FFI |
Most of the users and framework developers |
Input validation notes¶
oneDNN performs limited input validation to minimize the performance overheads. The user application is responsible for sanitizing inputs passed to the library. Examples of the inputs that may result in unexpected consequences:
Not-a-number (NaN) floating point values
Large
u8ors8inputs may lead to accumulator overflowWhile the
bf1616-bit floating point data type has range close to 32-bit floating point data type, there is a significant reduction in precision.
As oneDNN API accepts raw pointers as parameters it’s the calling code responsibility to
Allocate memory and validate the buffer sizes before passing them to the library
Ensure that the data buffers do not overlap unless the functionality explicitly permits in-place computations