How to fix "HDF5-DIAG: Error unable to open file"? - c

Question

When trying to run a MEEP simulation the following error appears:
HDF5-DIAG: Error detected in HDF5 (1.10.5) thread 0:
#000: H5F.c line 509 in H5Fopen(): unable to open file
major: File accessibilty
minor: Unable to open file
#001: H5Fint.c line 1498 in H5F_open(): unable to open file: time = Fri Nov 15 16:56:54 2019
, name = '*.h5', tent_flags = 0
major: File accessibilty
minor: Unable to open file
#002: H5FD.c line 734 in H5FD_open(): open failed
major: Virtual File Layer
minor: Unable to initialize object
#003: H5FDsec2.c line 346 in H5FD_sec2_open(): unable to open file: name = '*.h5', errno = 2, error message = 'No such file or directory', flags = 0, o_flags = 0
major: File accessibilty
minor: Unable to open file
h5topng error: error opening HD5 file
rm: *.h5: No such file or directory
Could somebody enlighten me on how to fix this/understand the error?
Thanks in advance

Answer 1

Disclaimer: I have never worked with MEEP.
The error seems to indicate taht the file doesn't exist:
#003: H5FDsec2.c line 346 in H5FD_sec2_open(): unable to open file: name = '*.h5', errno = 2, error message = 'No such file or directory', flags = 0, o_flags = 0
So this appears to be the core issue.
Going further down the rabbit hole it seems that the file name passed to H5FD_sec2_open() is *.h5 which is most likely an invalid file name. I expect you want to pass something such as foo.h5 or relative/path/to/foo.h5 or /absolute/path/to/foo.h5 to the H5FD_sec2_open() function.
The wildcard is something that is usually not handled/interpreted by these kinds of functions. It's a higher level concept and requires "more filesystem access" to do anything useful with it as whoever receives that wildcard has to get a list of files & directories and figure out which file system entries match this wildcard.
Therefore, my answer would be: Make sure that you pass a valid file path to the corresponding file opening function.
Furthermore, you might want to extend your program so that it checks whether it's a valid file before you pass it to the corresponding MEEP function which allows you to have better error and user feedback control.