Open or create HDF5 files. RAII-managed handles close automatically on scope exit.

File operations

H5CPP exposes two free functions for the HDF5 file lifecycle — h5::open and h5::create — both returning an h5::fd_t RAII handle. There is no explicit h5::close(fd): let the handle go out of scope and H5Fclose runs automatically.

h5::fd_t is the entry point for everything else — datasets, attributes, and groups all open relative to an fd_t. See Object handles for the broader handle taxonomy and the conversion rules to/from raw hid_t.

Operations

h5::create — create a new file
h5::open — open an existing file
Close: RAII (let h5::fd_t destruct, or static_cast<::hid_t> to consume)

Both calls take optional property lists to tune low-level behaviour (cache size, MPI communicator, file driver, …); the defaults work for the common cases.

Notes on lifetime

h5::fd_t follows the rule-of-five RAII contract from Object handles. Copies share the underlying HDF5 reference (via H5Iinc_ref); moves transfer ownership without bumping the refcount; destruction calls H5Fclose only when the last reference goes away.

Practical implication: passing an h5::fd_t by value to a function is cheap (refcount bump, no copy of file data) and the file stays open for as long as any handle exists.

void process(h5::fd_t fd) {                 // by value: refcount bump
    auto v = h5::read<std::vector<float>>(fd, "/grid");
}                                            // refcount decrements; file stays open if caller still holds
 
h5::fd_t outer = h5::open("data.h5", H5F_ACC_RDONLY);
process(outer);                              // outer still valid here

Cross-references

Object handles — the broader h5::*_t taxonomy
Conversion Policy — h5::fd_t ↔ hid_t
Property Lists — fcpl_t / fapl_t reference
Error Handling — the h5::error::io::file::* hierarchy
DATASET — read/write/append on an open file
ATTRIBUTES — metadata attached to file / groups / datasets
GROUPS — directory-like structure within a file