documentation typos and minor mistakes in netcdf-4 doxygen docs

[edhartnett]

Doxygen documentation fixes for netCDF-4 functions in libdispatch

Summary

A review of the Doxygen documentation for netCDF-4 functions in the libdispatch directory found and fixed a number of issues across 11 source files. The fixes are on PR #3265

Issues Found and Fixed

1. Grammar Error: "an netCDF-4" → "a netCDF-4"

The phrase "Not an netCDF-4 file" appeared ~25 times in NC_ENOTNC4 return descriptions. Since "netCDF" is pronounced with a leading consonant sound, the correct article is "a".

Files: dcompound.c (14), denum.c (5), dopaque.c (2), dvlen.c (4), dtype.c (3)

2. Typos

Eight typos were fixed across three files:

File	Typo	Correction
dvar.c	nc_creae()	nc_create()
dvar.c	scalare	scalar
dvar.c	wwere (2 occurrences)	were
dvar.c	preemtion	preemption
dfilter.c	Find the the param info	Find the param info
denum.c	user-define enumeration	user-defined enumeration
denum.c	about a about a member	about a member
dvlen.c	or and NC_OPAQUE	or an NC_OPAQUE

3. Incorrect @return on Stub Function

NC_NOTNC4_put_vlen_element() in dnotnc4.c documented @return ::NC_NOERR No error. but actually returns NC_ENOTNC4. Fixed to match the implementation.

4. Warning Buried in Prose (dvlen.c)

The important warning about nc_free_vlens() only working with fixed-size base types was plain text (WARNING:). Converted to a proper \warning Doxygen tag so it renders as a highlighted warning box in the generated documentation.

5. Missing @since Version Tags

Added @since tags to 9 functions that were introduced in specific releases but lacked version information:

Function	File	Version
nc_def_var_szip	dvar.c	4.0.0
nc_def_var_quantize	dvar.c	4.9.0
nc_inq_var_quantize	dvarinq.c	4.9.0
nc_def_var_bzip2	dfilter.c	4.9.0
nc_inq_var_bzip2	dfilter.c	4.9.0
nc_def_var_zstandard	dfilter.c	4.9.0
nc_inq_var_zstandard	dfilter.c	4.9.0
nc_def_var_blosc	dfilter.c	4.9.0
nc_inq_var_blosc	dfilter.c	4.9.0

6. Vague @returns in Group Functions (dgroup.c)

All 14 public functions in dgroup.c had only a generic @returns Error code or ::NC_NOERR for no error. with no specific error codes listed. Added specific error codes (e.g., NC_EBADID, NC_ENOTNC4, NC_ENOGRP, NC_ENOMEM, NC_EINVAL) derived from the actual NC4 implementations in libsrc4/nc4grp.c.

Also cleaned up nc_def_grp() which mixed @returns and @retval — now consistently uses @returns.

7. Missing @param Descriptions (denum.c)

Two parameters lacked description text:

• nc_insert_enum(): \param xtype had no description → added "Typeid of the enum type."
• nc_inq_enum_ident(): \param ncid had no description → added \ref ncid

8. Undocumented Stub Functions (dnotnc4.c)

Five internal stub functions had no Doxygen at all, unlike all other stubs in the same file. Added @internal doc blocks with parameter lists and accurate @return values:

• NC_NOTNC4_inq_var_filter_ids
• NC_NOTNC4_inq_var_filter_info
• NC_NOOP_inq_var_filter_ids
• NC_NOOP_inq_var_filter_info
• NC_NOOP_inq_filter_avail

9. Incomplete Code Example (dgroup.c)

The nc_def_grp() example was a stub that declared variables but never actually called nc_def_grp() — just ... and \endcode. Replaced with a complete working example that creates a netCDF-4 file, defines a group, and defines a dimension and variable inside it.

10. Inconsistent Example Section Naming

• dvarinq.c: nc_inq_varid_example4 and nc_inq_var_example5 had arbitrary numeric suffixes → renamed to nc_inq_varid_example and nc_inq_var_example
• dparallel.c: Two examples used raw HTML <h1>Example</h1> instead of Doxygen \section tags → converted to \section nc_create_par_example Example and @section nc_var_par_access_example Example

11. Missing @ingroup on Filter Functions (dfilter.c)

Five filter convenience functions lacked @ingroup variables, preventing them from appearing in the variables group in generated docs:

• nc_def_var_bzip2
• nc_inq_var_bzip2
• nc_def_var_zstandard
• nc_inq_var_zstandard
• nc_inq_var_blosc

(nc_def_var_blosc already had it.)

12. Missing @ingroup on Group Functions (dgroup.c)

All 14 functions in dgroup.c relied solely on the file-level \defgroup groups / \{ / \} block for group membership. Added explicit @ingroup groups to each function for robustness and consistency with other files like dcompound.c and denum.c.

Files Modified

File	Changes
libdispatch/dcompound.c	Grammar fix (14 occurrences)
libdispatch/denum.c	Grammar fix (5), typos (2), missing param descriptions (2)
libdispatch/dopaque.c	Grammar fix (2)
libdispatch/dvlen.c	Grammar fix (4), warning tag, typo
libdispatch/dtype.c	Grammar fix (3)
libdispatch/dvar.c	Typos (5), @since tags (2)
libdispatch/dvarinq.c	@since tag (1), example section names (2)
libdispatch/dfilter.c	Typo (1), @since tags (6), @ingroup tags (5)
libdispatch/dnotnc4.c	Incorrect @return (1), undocumented stubs (5)
libdispatch/dgroup.c	Specific error codes (14 functions), example (1), @ingroup tags (14)
libdispatch/dparallel.c	HTML → \section tags (2)