H5E_WALK is a macro that is mapped to either H5E_WALK1 or H5E_WALK2, depending on the needs of the application.
Such macros are provided to facilitate application compatibility. For more information on macro use and mappings, see the API Compatibility Macros in HDF5 document.
When both the HDF5 library and the application are built and installed with no specific compatibility flags, H5E_WALK is mapped to the most recent version of the function, currently H5E_WALK2. If the library and/or application is compiled for Release 1.6 emulation, H5E_WALK will be mapped to H5E_WALK1. 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:
Programming Note for C++ Developers Using C Functions:
If a C routine that takes a function pointer as an argument is called from within C++ code, the C routine should be returned from normally.
Examples of this kind of routine include callbacks such as H5P_SET_ELINK_CB and H5P_SET_TYPE_CONV_CB and functions such as H5T_CONVERT and H5E_WALK2.
Exiting the routine in its normal fashion allows the HDF5 C library to clean up its work properly. In other words, if the C++ application jumps out of the routine back to the C++ “catch” statement, the library is not given the opportunity to close any temporary data structures that were set up when the routine was called. The C++ application should save some state as the routine is started so that any problem that occurs might be diagnosed.
The function H5Ewalk renamed to H5Ewalk1 and deprecated in this release. The macro H5Ewalk and the function H5Ewalk2 introduced in this release.