H5P_REGISTER is a macro that is mapped to either H5P_REGISTER1 or H5P_REGISTER2, depending on the needs of the application.
Such macros are provided to facilitate application compatibility. For example:
- The H5P_REGISTER macro will be mapped to H5P_REGISTER1 and will use the H5P_REGISTER1 syntax (first signature above) if an application is coded for HDF5 Release 1.6.x.
- The H5P_REGISTER macro mapped to H5P_REGISTER2 and will use the H5P_REGISTER2 syntax (second signature above) if an application is coded for HDF5 Release 1.8.x.
When both the HDF5 library and the application are built and installed with no specific compatibility flags, H5P_REGISTER is mapped to the most recent version of the function, currently H5P_REGISTER2. If the library and/or application is compiled for Release 1.6 emulation, H5P_REGISTER will be mapped to H5P_REGISTER1. Function-specific flags are available to override these settings on a function-by-function basis when the application is compiled.
Specific compile-time compatibility flags and the resulting mappings are as follows:
|Compatibility setting||H5P_REGISTER mapping|
|No compatibility flag||H5P_REGISTER2 |
|Enable deprecated symbols||H5P_REGISTER2 |
|Disable deprecated symbols||H5P_REGISTER2 |
|Emulate Release 1.6 interface||H5P_REGISTER1 |
|H5Pregister_vers = 2 ||H5P_REGISTER2|
|H5Pregister_vers = 1|
For more information on macro use and mappings, see the API Compatibility Macros in HDF5 document.
Signature  above is the original H5P_REGISTER interface and the only interface available prior to HDF5 Release 1.8.0. This signature and the corresponding function are now deprecated but will remain directly callable as H5P_REGISTER1.
Signature  above was introduced with HDF5 Release 1.8.0 and is the recommended and default interface. It is directly callable as H5P_REGISTER2.
See API Compatibility Macros in HDF5 for circumstances under which either of these functions might not be available in an installed instance of the HDF5 library.