Change type of offset arg in H5Pset_external to HDoff_t

bin/trace

@@ -111,6 +111,7 @@ $Source = "";
                "H5M_iterate_t"              => 'MI',
                "H5FD_mem_t"                 => "Mt",
                "off_t"                      => "o",
+               "HDoff_t"                    => "Ho",
                "H5O_iterate1_t"             => "Oi",
                "H5O_iterate2_t"             => "OI",
                "H5O_mcdt_search_cb_t"       => "Os",

release_docs/RELEASE.txt

@@ -368,6 +368,22 @@ New Features
 
     Library:
     --------
+    - H5Pset_external() now uses HDoff_t, which is always a 64-bit type
+
+      The H5Pset_external() call took an off_t parameter in HDF5 1.14.x and
+      earlier. On POSIX systems, off_t is specified as a 64-bit type via
+      POSIX large-file support (LFS). On Windows, however, off_t is defined
+      as a 32-bit type, even on 64-bit Windows.
+
+      HDoff_t has been added to H5public.h and is defined to be __int64 on
+      Windows and the library has been updated to use HDoff_t in place of
+      off_t throughout. The H5Pset_external() offset parameter has also been
+      updated to be HDoff_t.
+
+      There is no API compatibility wrapper for this change.
+
+      Fixes GitHub issue #3506
+
     - Added support for _Float16 16-bit half-precision floating-point datatype
 
       Support for the _Float16 C datatype has been added on platforms where:

src/H5Pdcpl.c

@@ -2598,7 +2598,7 @@ H5Pget_chunk_opts(hid_t plist_id, unsigned *options /*out*/)
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pset_external(hid_t plist_id, const char *name, off_t offset, hsize_t size)
+H5Pset_external(hid_t plist_id, const char *name, HDoff_t offset, hsize_t size)
 {
     size_t          idx;
     hsize_t         total, tmp;
@@ -2607,7 +2607,7 @@ H5Pset_external(hid_t plist_id, const char *name, off_t offset, hsize_t size)
     herr_t          ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE4("e", "i*soh", plist_id, name, offset, size);
+    H5TRACE4("e", "i*sHoh", plist_id, name, offset, size);
 
     /* Check arguments */
     if (!name || !*name)

src/H5Ppublic.h

@@ -5669,6 +5669,7 @@ H5_DLL herr_t H5Pget_mpi_params(hid_t fapl_id, MPI_Comm *comm, MPI_Info *info);
  */
 H5_DLL herr_t H5Pset_mpi_params(hid_t fapl_id, MPI_Comm comm, MPI_Info info);
 #endif /* H5_HAVE_PARALLEL */
+
 /**
  * \ingroup FAPL
  *
@@ -6528,7 +6529,7 @@ H5_DLL herr_t H5Pset_dset_no_attrs_hint(hid_t dcpl_id, hbool_t minimize);
  * \since 1.0.0
  *
  */
-H5_DLL herr_t H5Pset_external(hid_t plist_id, const char *name, off_t offset, hsize_t size);
+H5_DLL herr_t H5Pset_external(hid_t plist_id, const char *name, HDoff_t offset, hsize_t size);
 /**
  * \ingroup DCPL
  *

src/H5private.h

@@ -661,16 +661,19 @@ typedef struct {
  */
 #include "H5win32defs.h"
 
-/* Platform-independent definitions for struct stat and off_t */
-#ifndef H5_HAVE_WIN32_API
-/* These definitions differ in Windows and are defined in
- * H5win32defs for that platform.
+/* Platform-independent definition for struct stat. For Win32, see
+ * H5win32defs.h.
  */
+#ifndef H5_HAVE_WIN32_API
 typedef struct stat h5_stat_t;
-typedef off_t       h5_stat_size_t;
-#define HDoff_t off_t
 #endif
 
+/* __int64 is the correct type for the st_size field of the _stati64
+ * struct on Windows (MSDN isn't very clear about this). POSIX systems use
+ * off_t. Both of these are typedef'd to HDoff_t in H5public.h.
+ */
+typedef HDoff_t h5_stat_size_t;
+
 /* Redefinions of some POSIX and C functions (mainly to deal with Windows) */
 
 #ifndef HDaccess

src/H5public.h

@@ -296,6 +296,22 @@ typedef long long ssize_t;
  */
 typedef uint64_t hsize_t;
 
+/* off_t exists on Windows, but is always a 32-bit long, even on 64-bit Windows,
+ * so on Windows we define HDoff_t to be __int64, which is the type of the
+ * st_size field of the _stati64 struct.
+ */
+#ifdef H5_HAVE_WIN32_API
+/**
+ * Platform-independent offset
+ */
+typedef __int64 HDoff_t;
+#else
+/**
+ * Platform-independent offset
+ */
+typedef off_t HDoff_t;
+#endif
+
 #ifdef H5_HAVE_PARALLEL
 #define HSIZE_AS_MPI_TYPE MPI_UINT64_T
 #endif

src/H5win32defs.h

@@ -20,17 +20,10 @@
 
 #ifdef H5_HAVE_WIN32_API
 
-/* off_t exists on Windows, but is always a 32-bit long, even on 64-bit Windows,
- * so we define HDoff_t to be __int64, which is the type of the st_size field
- * of the _stati64 struct and what is returned by _ftelli64().
- */
-#define HDoff_t __int64
-
-/* __int64 is the correct type for the st_size field of the _stati64 struct.
- * MSDN isn't very clear about this.
+/* Win32 platform-independent definition for struct stat. For POSIX, see
+ * H5private.h.
  */
 typedef struct _stati64 h5_stat_t;
-typedef __int64         h5_stat_size_t;
 
 #ifdef H5_HAVE_VISUAL_STUDIO
 struct timezone {