Here are the data types with brief descriptions:

[detail level 12]

▼Nfortranc	Utility module for supporting Fortran 2003 C language interface module
Cc_ptr_ptr	Fortran derived type for handling `void`, `char`, etc C objects (pointer to pointer or array of pointers)
Cstrlen	Equivalent of the strlen C function
Cstrtofchar	Convert a null-terminated C string into a Fortran `CHARACTER` variable of the proper length
Cc_ptr_ptr_new	Constructor for a c_ptr_ptr object
▼Ngdal	Fortran 2003 interface to the gdal http://www.gdal.org/ library
Cgdalapplygeotransform_f	Interface to a Fortran version of gdalapplygeotransform working on scalars, 1-d, 2-d and 3-d arrays
Cgdaldatasetrasterio_f	Simplified Fortran generic interface to the gdaldatasetrasterio C function
Cgdalrasterio_f	Simplified Fortran generic interface to the gdalrasterio C function
Cgdalmajorobjecth_new	Fortran interface for formally converting a dataset, rasterband or driver opaque object into a generic gdal object of type gdalmajorobjecth to be used in some methods such as GDALGetMetadata
▼Nproj	Fortran 2003 interface to the proj.4 https://github.com/OSGeo/proj.4 library
Cpj_object	Object describing a cartographic projection
Cpjuv_object	Object describing a coordinate pair
Cpj_associated	Test whether an opaque object is valid
Cpj_init_plus	Initialize a projection from a string
▼Nproj6	Fortran 2003 interface to the proj https://proj.org/ library, API version 6
Cpj_object	Object describing a projection or a transformation
Cpj_context_object	Object describing a proj multithread context
Cpj_coord_object	Object describing a general-purpose georeferenced coordinate
Cpj_area_object	Object describing a proj area
Cpj_info_object	Object strictly reflecting C PJ_INFO structure
Cpj_proj_info_object	Object strictly reflecting C PJ_PROJ_INFO structure
Cproj_associated	Test whether an opaque object is valid
▼Nreadosm	Fortran 2003 interface to the readosm https://www.gaia-gis.it/fossil/readosm/index library
Creadosm_tag	Object describing a TAG structure
Creadosm_tag_f	A more Fortran-friendly object describing a TAG structure
Creadosm_node	Object describing a NODE structure
Creadosm_node_f	A more Fortran-friendly object describing a NODE structure
Creadosm_way	Object describing a WAY structure
Creadosm_way_f	A more Fortran-friendly object describing a WAY structure
Creadosm_member	Object describing a RELATION-MEMBER structure
Creadosm_member_f	A more Fortran-friendly object describing a RELATION-MEMEBER structure
Creadosm_relation	Object describing a RELATION structure
Creadosm_relation_f	A more Fortran-friendly object describing a RELATION structure
Carrayof_readosm_node_f	Derived type defining a dynamically extensible array of TYPE(readosm_node_f) elements
Cinsert	Method for inserting elements of the array at a desired position
Cappend	Quick method to append an element to the array
Cremove	Method for removing elements of the array at a desired position
Cdelete	Destructor for finalizing an array object
Cpackarray	Method for packing the array object reducing at a minimum the memory occupation, without destroying its contents
Carrayof_readosm_way_f	Derived type defining a dynamically extensible array of TYPE(readosm_way_f) elements
Carrayof_readosm_relation_f	Derived type defining a dynamically extensible array of TYPE(readosm_relation_f) elements
Creadosm_full_f	Derived type for performing a prepackaged full parsing of an osm file
Creadosm_open	Open the .osm or .pbf file, preparing for future functions
Creadosm_close	Close the .osm or .pbf file and release any allocated resource
Creadosm_parse	Parse the corresponding file calling the selected callbacks for every entity encountered
▼Nshapelib	Fortran 2003 interface to the shapelib http://shapelib.maptools.org/ library
Cshpfileobject	Object describing a shapefile dataset
Cshpobject	Object describing the geometrical properties of a shape
Cdbfreadattribute	Interface to SUBROUTINEs for reading dbf attributes
Cdbfwriteattribute	Interface to FUNCTIONs for setting dbf attributes