diff --git a/CLAUDE.md b/CLAUDE.md
index 05e6d4cb..8347cb7a 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -103,9 +103,9 @@ A library `libshadowsocks-c` (legacy names `libshadowsocks-libev.*` are kept) is
 
 **Shared by all binaries:**
 - `utils.c` - logging, system utilities, `ss_malloc`/`ss_free`
-- `jconf.c` / `json.c` - JSON config file parsing
+- `jconf.c` / `json.cpp` - JSON config file parsing
 - `netutils.c` - network address utilities
-- `cache.c` - uthash-based connection cache (UDP relay, AEAD-2022 tables)
+- `cache.cpp` - uthash-based connection cache (UDP relay, AEAD-2022 tables)
 - `udprelay.c` - UDP relay implementation (shared, but uses `#ifdef MODULE_*` for per-binary behavior)
 - `ss_event.c` / `ss_event.h` - event loop API over libuv
 - `resolv.c` - asynchronous DNS via c-ares
@@ -115,11 +115,11 @@ A library `libshadowsocks-c` (legacy names `libshadowsocks-libev.*` are kept) is
 - `stream.c` - legacy stream ciphers
 - `aead.c` - AEAD ciphers (AES-GCM via Mbed TLS/libsodium, ChaCha20-Poly1305 via libsodium)
 - `aead2022.c` / `aead2022_udp.c` - Shadowsocks 2022 (SIP022), BLAKE3 from `src/blake3`
-- `ppbloom.c` - ping-pong bloom filter for salt replay detection (`third_party/bloom`)
+- `ppbloom.cpp` - ping-pong bloom filter for salt replay detection (`third_party/bloom`)
 
-**ACL:** `acl.c` / `rule.c` / `ipset.c` - IP prefix sets and PCRE2/literal domain rules.
+**ACL:** `acl.c` / `rule.cpp` / `ipset.cpp` - IP prefix sets and PCRE2/literal domain rules.
 
-**Plugins:** `plugin.c` / `process.c` - SIP003 plugin subprocess management.
+**Plugins:** `plugin.c` / `process.cpp` - SIP003 plugin subprocess management.
 
 **C++ core:** `src/core/*.hpp` - header-only ownership and allocation primitives (pools, handles, fixed
 buffers, arena, fixed hash map/LRU, intrusive list, bounded heap). See `docs/cpp-core.md`.
diff --git a/cmake/ProjectOptions.cmake b/cmake/ProjectOptions.cmake
index f73366a8..82726baa 100644
--- a/cmake/ProjectOptions.cmake
+++ b/cmake/ProjectOptions.cmake
@@ -26,9 +26,11 @@ function(ss_project_options target)
     else()
         target_compile_options(${target} PRIVATE -Wall -Wno-deprecated-declarations -fno-strict-aliasing)
         # C++ sources: no exceptions or RTTI, and no locks around function
-        # statics (the event loop is single-threaded).
+        # statics (the event loop is single-threaded). New C++ code also opts
+        # into -Wextra through ss_strict_warnings(); modules ported from C get
+        # it when they are rewritten.
         target_compile_options(${target} PRIVATE
-            $<$<COMPILE_LANGUAGE:CXX>:-Wextra -fno-exceptions -fno-rtti -fno-threadsafe-statics>)
+            $<$<COMPILE_LANGUAGE:CXX>:-fno-exceptions -fno-rtti -fno-threadsafe-statics>)
         if(SS_WARNINGS_AS_ERRORS)
             target_compile_options(${target} PRIVATE -Werror)
         endif()
@@ -54,3 +56,11 @@ function(ss_project_options target)
         target_link_options(${target} PRIVATE --coverage)
     endif()
 endfunction()
+
+# Extra warnings for code written as C++ from the start (src/core and its
+# tests).
+function(ss_strict_warnings target)
+    if(NOT MSVC)
+        target_compile_options(${target} PRIVATE $<$<COMPILE_LANGUAGE:CXX>:-Wextra>)
+    endif()
+endfunction()
diff --git a/debian/copyright b/debian/copyright
index aa8e2484..148d692f 100644
--- a/debian/copyright
+++ b/debian/copyright
@@ -41,11 +41,11 @@ Files: scripts/build_deb.sh
 Copyright: 2018 Roger Shimizu <rosh@debian.org>
 License: GPL-3+
 
-Files: src/base64.c src/base64.h
+Files: src/base64.cpp src/base64.h
 Copyright: 2006 Ryan Martell <rdm4@martellventures.com>
 License: LGPL-2.1+
 
-Files: src/json.c src/json.h
+Files: src/json.cpp src/json.h
 Copyright: 2012-2014, James McLaughlin et al.
 License: BSD-2-clause
 
@@ -53,7 +53,7 @@ Files: src/resolv.c src/resolv.h
 Copyright: 2011-2014, Dustin Lundquist <dustin@null-ptr.net>
 License: BSD-2-clause
 
-Files: src/rule.c src/rule.h
+Files: src/rule.cpp src/rule.h
 Copyright: 2011-2012, Dustin Lundquist <dustin@null-ptr.net>
            2011, Manuel Kasper <mk@neon1.net>
 License: BSD-2-clause
diff --git a/docs/cpp-core.md b/docs/cpp-core.md
index 24ecf11e..ab21d5cb 100644
--- a/docs/cpp-core.md
+++ b/docs/cpp-core.md
@@ -43,7 +43,7 @@ All binaries are still built from the C sources.
 | `ref.hpp` | `RefCounted<T>`/`RefPtr<T>`, intrusive shared ownership for the few genuinely shared objects (AEAD-2022 UDP sessions). Used instead of `std::shared_ptr` because its control block cannot be pooled portably. |
 | `buffer.hpp` | `FixedBuffer<N>`: inline bytes with `std::span` views; replaces `buffer_t`. |
 | `arena.hpp` | `MonotonicArena` for configuration data that lives as long as the process. |
-| `fixed_map.hpp` | `FixedHashMap` (open addressing, backward-shift deletion) and `FixedLru`; replace uthash and `cache.c`. |
+| `fixed_map.hpp` | `FixedHashMap` (open addressing, backward-shift deletion) and `FixedLru`; replace uthash and `cache.cpp`. |
 | `intrusive_list.hpp` | `IntrusiveList`/`ListNode`; replaces `ss_list`. Nodes unlink themselves when destroyed. |
 | `fixed_heap.hpp` | Bounded size-class allocator to hand to libuv, c-ares and Mbed TLS through their allocator hooks. |
 
diff --git a/scripts/check_cxx_runtime.py b/scripts/check_cxx_runtime.py
new file mode 100644
index 00000000..a1276d8b
--- /dev/null
+++ b/scripts/check_cxx_runtime.py
@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-3.0-or-later
+"""Fail if programs or libraries need the C++ runtime library.
+
+The C++ core is built without exceptions or RTTI and uses only header-only
+parts of the standard library, so the programs and libshadowsocks-c stay
+consumable from plain C: a C program linking libshadowsocks-c.a must not need
+libstdc++ or libc++. This script lists the undefined symbols of each file with
+nm and rejects anything served by the C++ runtime (operator new/delete,
+exception and RTTI support, std:: functions).
+
+Usage: check_cxx_runtime.py [--nm NM] FILE...
+"""
+
+import argparse
+import re
+import shutil
+import subprocess
+import sys
+
+# Itanium-ABI names (with or without the Mach-O leading underscore) that only
+# the C++ runtime defines.
+RUNTIME = re.compile(
+    r"^_?(?:"
+    r"_Zn[wa]|_Zd[la]|"                     # operator new / delete
+    r"_ZSt|_ZNSt|_ZNKSt|"                    # std:: functions and members
+    r"_ZTI|_ZTS|_ZTV|"                       # typeinfo / vtables (RTTI, classes from the runtime)
+    r"__cxa_(?!atexit$|finalize$|thread_atexit_impl$)|"  # exception/guard support; libc owns these three
+    r"__gxx_personality|_Unwind_|__dynamic_cast"
+    r")"
+)
+
+
+def undefined_symbols(nm, path):
+    result = subprocess.run([nm, "-u", path], capture_output=True, text=True)
+    if result.returncode != 0:
+        raise SystemExit(f"{nm} failed on {path}: {result.stderr.strip()}")
+    symbols = set()
+    for line in result.stdout.splitlines():
+        line = line.strip()
+        if not line or line.endswith(":"):
+            continue  # archive member headers
+        symbols.add(line.split()[-1])
+    return symbols
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
+    parser.add_argument("--nm", default=shutil.which("nm") or "nm")
+    parser.add_argument("files", nargs="+")
+    args = parser.parse_args()
+    failed = False
+    for path in args.files:
+        bad = sorted(s for s in undefined_symbols(args.nm, path) if RUNTIME.match(s))
+        if bad:
+            failed = True
+            print(f"{path}: needs the C++ runtime:")
+            for symbol in bad:
+                print(f"    {symbol}")
+        else:
+            print(f"{path}: ok")
+    return 1 if failed else 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/scripts/check_no_heap.py b/scripts/check_no_heap.py
index 39fa63b6..7675efbb 100644
--- a/scripts/check_no_heap.py
+++ b/scripts/check_no_heap.py
@@ -14,7 +14,12 @@ A line that must allocate (a startup reservation) carries a justification:
 
     void *base = std::calloc(1, size); // heap-ok: startup reservation
 
-Usage: check_no_heap.py [--root DIR] [--self-test]
+Modules converted mechanically from C still allocate the way the C code did
+until they are rewritten. scripts/no_heap_baseline.txt lists them with their
+current violation counts, and works as a ratchet: a file may not gain
+violations, and when it loses some the baseline must be lowered to match.
+
+Usage: check_no_heap.py [--root DIR] [--baseline FILE] [--self-test]
 """
 
 import argparse
@@ -89,16 +94,42 @@ def check_text(text):
     return problems
 
 
-def check_tree(root):
+def read_baseline(path):
+    baseline = {}
+    if path is None or not path.exists():
+        return baseline
+    for raw in path.read_text(encoding="utf-8").splitlines():
+        line = raw.split("#", 1)[0].strip()
+        if line:
+            name, count = line.split()
+            baseline[name] = int(count)
+    return baseline
+
+
+def check_tree(root, baseline):
     src = root / "src"
     files = sorted(p for p in src.rglob("*") if p.suffix in (".cpp", ".hpp") and "blake3" not in p.parts)
-    failures = 0
+    ok = True
+    total = 0
     for path in files:
-        for number, why, line in check_text(path.read_text(encoding="utf-8")):
-            print(f"{path.relative_to(root)}:{number}: {why}: {line}")
-            failures += 1
-    print(f"check_no_heap: {len(files)} C++ files, {failures} violation(s)")
-    return failures == 0
+        name = path.relative_to(root).as_posix()
+        problems = check_text(path.read_text(encoding="utf-8"))
+        allowed = baseline.pop(name, 0)
+        total += len(problems)
+        if len(problems) > allowed:
+            for number, why, line in problems:
+                print(f"{name}:{number}: {why}: {line}")
+            print(f"{name}: {len(problems)} violation(s), baseline allows {allowed}")
+            ok = False
+        elif len(problems) < allowed:
+            print(f"{name}: {len(problems)} violation(s), below the baseline of {allowed}; "
+                  "lower it in scripts/no_heap_baseline.txt")
+            ok = False
+    for name in sorted(baseline):
+        print(f"{name}: listed in the baseline but not a C++ source; remove the entry")
+        ok = False
+    print(f"check_no_heap: {len(files)} C++ files, {total} baselined or new violation(s)")
+    return ok
 
 
 def self_test():
@@ -144,11 +175,15 @@ def self_test():
 def main():
     parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
     parser.add_argument("--root", type=pathlib.Path, default=pathlib.Path(__file__).resolve().parent.parent)
+    parser.add_argument("--baseline", type=pathlib.Path,
+                        help="ratchet file (default: scripts/no_heap_baseline.txt under --root)")
     parser.add_argument("--self-test", action="store_true", help="run the pattern self-test first")
     args = parser.parse_args()
     if args.self_test and not self_test():
         return 1
-    return 0 if check_tree(args.root.resolve()) else 1
+    root = args.root.resolve()
+    baseline = read_baseline(args.baseline or root / "scripts" / "no_heap_baseline.txt")
+    return 0 if check_tree(root, baseline) else 1
 
 
 if __name__ == "__main__":
diff --git a/scripts/no_heap_baseline.txt b/scripts/no_heap_baseline.txt
new file mode 100644
index 00000000..6cedf8e0
--- /dev/null
+++ b/scripts/no_heap_baseline.txt
@@ -0,0 +1,10 @@
+# Heap-allocation ratchet for C++ sources converted mechanically from C.
+# Format: <path> <violations>. check_no_heap.py fails if a file gains
+# violations, and also when it loses some, so the number here always goes
+# down. Remove a file once it is rewritten on the src/core primitives.
+src/cache.cpp 3
+src/ipset.cpp 3
+src/json.cpp 2
+src/process.cpp 26
+src/rule.cpp 2
+src/ssurl.cpp 3
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 255bd791..fe150898 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -10,8 +10,8 @@ endif ()
 
 set(SS_ACL_SOURCE
         acl.c
-        ipset.c
-        rule.c
+        ipset.cpp
+        rule.cpp
         )
 
 set(SS_CRYPTO_SOURCE
@@ -19,7 +19,7 @@ set(SS_CRYPTO_SOURCE
         aead.c
         aead2022.c
         aead2022_udp.c
-        base64.c
+        base64.cpp
         )
 
 # BLAKE3 (vendored) provides the key derivation for the 2022 ciphers. Only
@@ -43,16 +43,16 @@ if(SS_ENABLE_LEGACY)
     list(APPEND SS_CRYPTO_SOURCE stream.c)
 endif()
 if(SS_ENABLE_PLUGINS)
-    set(SS_PLUGIN_SOURCE plugin.c process.c)
+    set(SS_PLUGIN_SOURCE plugin.c process.cpp)
 else()
     set(SS_PLUGIN_SOURCE plugin_disabled.c)
 endif()
 
 set(SS_SHARED_SOURCES
-        ppbloom.c
+        ppbloom.cpp
         utils.c
         jconf.c
-        json.c
+        json.cpp
         netutils.c
         )
 if (MINGW)
@@ -62,10 +62,10 @@ endif ()
 set(LIBSHADOWSOCKS_LIBEV_SOURCE
         ${SS_SHARED_SOURCES}
         udprelay.c
-        cache.c
+        cache.cpp
         local.c
         resolv.c
-        ssurl.c
+        ssurl.cpp
         ${SS_CRYPTO_SOURCE}
         ${SS_PLUGIN_SOURCE}
         ${SS_ACL_SOURCE}
@@ -79,7 +79,7 @@ set(SS_LOCAL_SOURCE
 set(SS_TUNNEL_SOURCE
         ${SS_SHARED_SOURCES}
         udprelay.c
-        cache.c
+        cache.cpp
         tunnel.c
         ${SS_CRYPTO_SOURCE}
         ${SS_PLUGIN_SOURCE}
@@ -88,7 +88,7 @@ set(SS_TUNNEL_SOURCE
 set(SS_SERVER_SOURCE
         ${SS_SHARED_SOURCES}
         udprelay.c
-        cache.c
+        cache.cpp
         resolv.c
         server.c
         ${SS_CRYPTO_SOURCE}
@@ -104,7 +104,7 @@ set(SS_MANAGER_SOURCE
 set(SS_REDIR_SOURCE
         ${SS_SHARED_SOURCES}
         udprelay.c
-        cache.c
+        cache.cpp
         redir.c
         ${SS_CRYPTO_SOURCE}
         ${SS_PLUGIN_SOURCE}
diff --git a/src/base64.c b/src/base64.cpp
similarity index 100%
rename from src/base64.c
rename to src/base64.cpp
diff --git a/src/cache.c b/src/cache.cpp
similarity index 100%
rename from src/cache.c
rename to src/cache.cpp
diff --git a/src/core/fixed_map.hpp b/src/core/fixed_map.hpp
index 0385f021..a821e313 100644
--- a/src/core/fixed_map.hpp
+++ b/src/core/fixed_map.hpp
@@ -2,7 +2,7 @@
 #ifndef SS_CORE_FIXED_MAP_HPP
 #define SS_CORE_FIXED_MAP_HPP
 
-// Fixed-capacity associative containers. Replace uthash (cache.c,
+// Fixed-capacity associative containers. Replace uthash (cache.cpp,
 // ss_event.c, manager.c) without any per-entry allocation.
 //
 // FixedHashMap<K, V>
@@ -15,7 +15,7 @@
 // FixedLru<K, V>
 //     Map plus recency order. Values live in a slab and never move, so the
 //     pointer returned by insert() or find() stays valid until that entry
-//     is erased or evicted. Replaces the pseudo-LRU in cache.c.
+//     is erased or evicted. Replaces the pseudo-LRU in cache.cpp.
 //
 // Keys from the network (UDP peer addresses, session IDs) are hashed with a
 // per-table seed. Seed it from a CSPRNG in production code so a peer cannot
diff --git a/src/ipset.c b/src/ipset.cpp
similarity index 100%
rename from src/ipset.c
rename to src/ipset.cpp
diff --git a/src/json.c b/src/json.cpp
similarity index 100%
rename from src/json.c
rename to src/json.cpp
diff --git a/src/ppbloom.c b/src/ppbloom.cpp
similarity index 100%
rename from src/ppbloom.c
rename to src/ppbloom.cpp
diff --git a/src/process.c b/src/process.cpp
similarity index 100%
rename from src/process.c
rename to src/process.cpp
diff --git a/src/rule.c b/src/rule.cpp
similarity index 100%
rename from src/rule.c
rename to src/rule.cpp
diff --git a/src/ssurl.c b/src/ssurl.cpp
similarity index 100%
rename from src/ssurl.c
rename to src/ssurl.cpp
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index c950432c..49145de9 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -60,6 +60,7 @@ endfunction()
 # C++ core (src/core): header-only ownership and allocation primitives.
 foreach(core_test result pool buffer arena fixed_map ownership)
     ss_add_test(test_core_${core_test} "test_core_${core_test}.cpp" "")
+    ss_strict_warnings(test_core_${core_test})
 endforeach()
 
 # C++ sources under src/ must not allocate on the heap (see the script).
@@ -68,11 +69,30 @@ if(Python3_Interpreter_FOUND)
     add_test(NAME check_no_heap
         COMMAND ${Python3_EXECUTABLE} ${PROJECT_SOURCE_DIR}/scripts/check_no_heap.py --self-test)
     set_tests_properties(check_no_heap PROPERTIES LABELS "unit")
+
+    # The programs and the static library must stay usable without a C++
+    # runtime library (see docs/cpp-core.md). Sanitizer runtimes bring their
+    # own C++ symbols, so skip the check there.
+    set(SS_RUNTIME_CHECKED)
+    foreach(target ss-local ss-server ss-tunnel ss-redir ss-manager shadowsocks-c-static)
+        if(TARGET ${target})
+            get_target_property(excluded ${target} EXCLUDE_FROM_ALL)
+            if(NOT excluded)
+                list(APPEND SS_RUNTIME_CHECKED $<TARGET_FILE:${target}>)
+            endif()
+        endif()
+    endforeach()
+    if(SS_RUNTIME_CHECKED AND CMAKE_NM AND NOT ENABLE_SANITIZERS)
+        add_test(NAME check_cxx_runtime
+            COMMAND ${Python3_EXECUTABLE} ${PROJECT_SOURCE_DIR}/scripts/check_cxx_runtime.py
+                    --nm ${CMAKE_NM} ${SS_RUNTIME_CHECKED})
+        set_tests_properties(check_cxx_runtime PROPERTIES LABELS "unit")
+    endif()
 endif()
 
 # test_base64 - no external deps
 ss_add_test(test_base64
-    "test_base64.c;${PROJECT_SOURCE_DIR}/src/base64.c"
+    "test_base64.c;${PROJECT_SOURCE_DIR}/src/base64.cpp"
     "")
 
 # test_utils - needs sodium (for ss_malloc -> uses sodium in utils.c)
@@ -82,12 +102,12 @@ ss_add_test(test_utils
 
 # test_json - standalone json parser
 ss_add_test(test_json
-    "test_json.c;${PROJECT_SOURCE_DIR}/src/json.c"
+    "test_json.c;${PROJECT_SOURCE_DIR}/src/json.cpp"
     "${SS_MATH_LIBRARY}")
 
 # test_ssurl - ss:// URI parsing (SIP002 and legacy)
 ss_add_test(test_ssurl
-    "test_ssurl.c;${PROJECT_SOURCE_DIR}/src/ssurl.c;${PROJECT_SOURCE_DIR}/src/base64.c;${PROJECT_SOURCE_DIR}/src/utils.c"
+    "test_ssurl.c;${PROJECT_SOURCE_DIR}/src/ssurl.cpp;${PROJECT_SOURCE_DIR}/src/base64.cpp;${PROJECT_SOURCE_DIR}/src/utils.c"
     "ss_sodium")
 
 # test_netutils - address parsing and resolver integration
@@ -102,14 +122,14 @@ ss_add_test(test_netutils
 
 # test_cache - expiration uses a platform monotonic clock
 ss_add_test(test_cache
-    "test_cache.c;${PROJECT_SOURCE_DIR}/src/cache.c;${PROJECT_SOURCE_DIR}/src/utils.c"
+    "test_cache.c;${PROJECT_SOURCE_DIR}/src/cache.cpp;${PROJECT_SOURCE_DIR}/src/utils.c"
     "ss_sodium")
 
 # test_ppbloom - needs bloom
 set(TEST_PPBLOOM_LIBS "")
 list(APPEND TEST_PPBLOOM_LIBS bloom)
 ss_add_test(test_ppbloom
-    "test_ppbloom.c;${PROJECT_SOURCE_DIR}/src/ppbloom.c;${PROJECT_SOURCE_DIR}/src/utils.c"
+    "test_ppbloom.c;${PROJECT_SOURCE_DIR}/src/ppbloom.cpp;${PROJECT_SOURCE_DIR}/src/utils.c"
     "${TEST_PPBLOOM_LIBS};ss_sodium;${SS_MATH_LIBRARY}")
 
 if(SS_ENABLE_REGEX)
@@ -119,13 +139,13 @@ set(TEST_RULE_LIBS
     ss_sodium
 )
 ss_add_test(test_rule
-    "test_rule.c;${PROJECT_SOURCE_DIR}/src/rule.c;${PROJECT_SOURCE_DIR}/src/utils.c"
+    "test_rule.c;${PROJECT_SOURCE_DIR}/src/rule.cpp;${PROJECT_SOURCE_DIR}/src/utils.c"
     "${TEST_RULE_LIBS}")
 
 # test_acl - ACL precedence and prefix matching
 set(TEST_ACL_LIBS ${TEST_RULE_LIBS})
 ss_add_test(test_acl
-    "test_acl.c;${PROJECT_SOURCE_DIR}/src/acl.c;${PROJECT_SOURCE_DIR}/src/ipset.c;${PROJECT_SOURCE_DIR}/src/rule.c;${PROJECT_SOURCE_DIR}/src/utils.c"
+    "test_acl.c;${PROJECT_SOURCE_DIR}/src/acl.c;${PROJECT_SOURCE_DIR}/src/ipset.cpp;${PROJECT_SOURCE_DIR}/src/rule.cpp;${PROJECT_SOURCE_DIR}/src/utils.c"
     "${TEST_ACL_LIBS}")
 
 endif()
@@ -137,7 +157,7 @@ set(TEST_JCONF_LIBS
     ss_cares
 )
 ss_add_test(test_jconf
-    "test_jconf.c;${PROJECT_SOURCE_DIR}/src/jconf.c;${PROJECT_SOURCE_DIR}/src/json.c;${PROJECT_SOURCE_DIR}/src/utils.c;${PROJECT_SOURCE_DIR}/src/netutils.c"
+    "test_jconf.c;${PROJECT_SOURCE_DIR}/src/jconf.c;${PROJECT_SOURCE_DIR}/src/json.cpp;${PROJECT_SOURCE_DIR}/src/utils.c;${PROJECT_SOURCE_DIR}/src/netutils.c"
     "${TEST_JCONF_LIBS};${SS_MATH_LIBRARY}")
 
 # Crypto sources shared by the tests that link the crypto layer. The AEAD-2022
@@ -148,9 +168,9 @@ set(SS_CRYPTO_TEST_SOURCES
     ${PROJECT_SOURCE_DIR}/src/aead.c
     ${PROJECT_SOURCE_DIR}/src/aead2022.c
     ${PROJECT_SOURCE_DIR}/src/aead2022_udp.c
-    ${PROJECT_SOURCE_DIR}/src/ppbloom.c
-    ${PROJECT_SOURCE_DIR}/src/cache.c
-    ${PROJECT_SOURCE_DIR}/src/base64.c
+    ${PROJECT_SOURCE_DIR}/src/ppbloom.cpp
+    ${PROJECT_SOURCE_DIR}/src/cache.cpp
+    ${PROJECT_SOURCE_DIR}/src/base64.cpp
     ${PROJECT_SOURCE_DIR}/src/utils.c
 )
 
@@ -200,11 +220,11 @@ add_test(NAME test_ss_setup
 set_tests_properties(test_ss_setup PROPERTIES LABELS "integration")
 
 ss_add_test(test_ipset
-    "test_ipset.c;${PROJECT_SOURCE_DIR}/src/ipset.c;${PROJECT_SOURCE_DIR}/src/utils.c"
+    "test_ipset.c;${PROJECT_SOURCE_DIR}/src/ipset.cpp;${PROJECT_SOURCE_DIR}/src/utils.c"
     "ss_sodium")
 
 ss_add_test(test_process
-    "test_process.c;${PROJECT_SOURCE_DIR}/src/process.c;${PROJECT_SOURCE_DIR}/src/utils.c"
+    "test_process.c;${PROJECT_SOURCE_DIR}/src/process.cpp;${PROJECT_SOURCE_DIR}/src/utils.c"
     "ss_sodium")
 set_tests_properties(test_process PROPERTIES TIMEOUT 20)
 
@@ -218,7 +238,7 @@ if(SS_ENABLE_REGEX)
     list(APPEND TEST_LITERAL_LIBS ss_pcre2)
 endif()
 ss_add_test(test_acl_literal
-    "test_acl_literal.c;${PROJECT_SOURCE_DIR}/src/acl.c;${PROJECT_SOURCE_DIR}/src/ipset.c;${PROJECT_SOURCE_DIR}/src/rule.c;${PROJECT_SOURCE_DIR}/src/utils.c"
+    "test_acl_literal.c;${PROJECT_SOURCE_DIR}/src/acl.c;${PROJECT_SOURCE_DIR}/src/ipset.cpp;${PROJECT_SOURCE_DIR}/src/rule.cpp;${PROJECT_SOURCE_DIR}/src/utils.c"
     "${TEST_LITERAL_LIBS}")
 
 ss_add_test(test_event "test_event.c" "ss_ev")