Disable HDF5 locking with library version 1.10 (POSIX), clean close

hdf5_clean_close.hpp

#include<H5cpp.h>
#include<sys/file.h>
#include<iostream>

/* With libhdf5 1.10, file gets locked but the lock is not removed at close.
Thus opening the file from the same process will fail.
This function will force unlock before the file is closed.

3 things must be done, in this order:

1. flush the file
2. unlock
3. close

*/

void hdf5_unlock_close(H5::H5File& h5file){
	#if H5_VERSION_GE(1,11,0)
		#error "Better use HDF5_USE_FILE_LOCKING=FALSE to disable locking with HDF5>=1.11" 
	#endif
	h5file.flush(H5F_SCOPE_GLOBAL);
	int *handle;
	h5file.getVFDHandle((void**)&handle);
	int err=flock(*handle,LOCK_UN);
	if(err) std::cerr<<"flock failed: "<<strerror(errno));
	h5file.close();
}