Fixes C++ sign-conversion warnings w/ clang 14 (#1870)

* Fixes sign-conversion warnings w/ clang 14

* Committing clang-format changes

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/c++/src/H5Location.cpp b/c++/src/H5Location.cpp
index 915f2a9..e128303 100644
--- a/c++/src/H5Location.cpp
+++ b/c++/src/H5Location.cpp
@@ -363,7 +363,7 @@ H5Location::getComment(const char *name, size_t buf_size) const
 
         // If buffer size is not provided, use comment length
         if (tmp_len == 0)
-            tmp_len = comment_len;
+            tmp_len = static_cast<size_t>(comment_len);
 
         // Temporary buffer for char* comment
         char *comment_C = new char[tmp_len + 1]();
@@ -2044,11 +2044,15 @@ H5Location::getObjnameByIdx(hsize_t idx) const
     if (name_len < 0)
         throwException("getObjnameByIdx", "H5Lget_name_by_idx failed");
 
+    // The actual size is the cast value + 1 for the terminal ASCII NUL
+    // (unfortunate in/out type sign mismatch)
+    size_t actual_name_len = static_cast<size_t>(name_len) + 1;
+
     // Create buffer for C string
-    char *name_C = new char[name_len + 1]();
+    char *name_C = new char[actual_name_len]();
 
-    name_len =
-        H5Lget_name_by_idx(getId(), ".", H5_INDEX_NAME, H5_ITER_INC, idx, name_C, name_len + 1, H5P_DEFAULT);
+    name_len = H5Lget_name_by_idx(getId(), ".", H5_INDEX_NAME, H5_ITER_INC, idx, name_C, actual_name_len,
+                                  H5P_DEFAULT);
 
     if (name_len < 0) {
         delete[] name_C;