Debugging output for all packages except datatypes and data spaces will appear on the standard error stream. This disables all debugging even if the default was to debug something, then output from the meta data cache is send to the standard error stream and output from data types and spaces is sent to file descriptor 255 which should be redirected by the shell. Tracing The HDF5 library can trace API calls by printing the function name, the argument names and their values, and the return value. Some people like to see lots of output during program execution instead of using a good symbolic debugger, and this feature is intended for their consumption. Error detected in thread 0.
Back trace follows.
If the library was not configured for tracing then there is no unnecessary overhead since all tracing code is excluded. However, if tracing is enabled but not used there is a small penalty. First, code size is larger because of extra statically-declared character strings used to store argument types and names and extra auto variable pointer in each function. If tracing is enabled and turned on then the penalties from the previous paragraph apply plus the time required to format each line of tracing information. The tracing mechanism is invoked for each API function before arguments are checked for validity.