diff --git a/include/pcg_extras.hpp b/include/pcg_extras.hpp
index ec3e569..d4c710d 100644
--- a/include/pcg_extras.hpp
+++ b/include/pcg_extras.hpp
@@ -135,7 +135,7 @@ operator<<(std::basic_ostream<CharT,Traits>& out, pcg128_t value)
         }
         if (highpart != 0 || desired_width > 16)
             out << highpart;
-        CharT oldfill;
+        CharT oldfill = '\0';
         if (highpart != 0) {
             out.width(16);
             oldfill = out.fill('0');
@@ -156,7 +156,7 @@ operator<<(std::basic_ostream<CharT,Traits>& out, pcg128_t value)
     constexpr auto BASE = pcg128_t(10ULL);
     do {
         auto div = value / BASE;
-        auto mod = uint32_t(value - (div * BASE));
+        auto mod = char(value % BASE);
         *(--pos) = '0' + mod;
         value = div;
     } while(value != pcg128_t(0ULL));
@@ -220,7 +220,7 @@ operator<<(std::basic_ostream<CharT,Traits>&out, uint8_t value)
 
 template <typename CharT, typename Traits>
 std::basic_istream<CharT,Traits>&
-operator>>(std::basic_istream<CharT,Traits>& in, uint8_t target)
+operator>>(std::basic_istream<CharT,Traits>& in, uint8_t& target)
 {
     uint32_t value = 0xdecea5edU;
     in >> value;
@@ -393,7 +393,7 @@ SrcIter uneven_copy_impl(
     constexpr bitcount_t SCALE     = SRC_SIZE / DEST_SIZE;
 
     size_t count = 0;
-    src_t value;
+    src_t value = 0;
 
     while (dest_first != dest_last) {
         if ((count++ % SCALE) == 0)
@@ -483,10 +483,10 @@ void generate_to_impl(SeedSeq&& generator, DestIter dest,
         generator.generate(buffer, buffer+FROM_ELEMS);
         uneven_copy(buffer, dest, dest+size);
     } else {
-        uint32_t* buffer = (uint32_t*) malloc(GEN_SIZE * FROM_ELEMS);
+        uint32_t* buffer = static_cast<uint32_t*>(malloc(GEN_SIZE * FROM_ELEMS));
         generator.generate(buffer, buffer+FROM_ELEMS);
         uneven_copy(buffer, dest, dest+size);
-        free(buffer);
+        free(static_cast<void*>(buffer));
     }
 }
 
@@ -531,13 +531,14 @@ template <typename Iter, typename RandType>
 void shuffle(Iter from, Iter to, RandType&& rng)
 {
     typedef typename std::iterator_traits<Iter>::difference_type delta_t;
+    typedef typename std::remove_reference<RandType>::type::result_type result_t;
     auto count = to - from;
     while (count > 1) {
-        delta_t chosen(bounded_rand(rng, count));
+        delta_t chosen = delta_t(bounded_rand(rng, result_t(count)));
         --count;
         --to;
         using std::swap;
-        swap(*(from+chosen), *to);
+        swap(*(from + chosen), *to);
     }
 }
 
@@ -620,11 +621,11 @@ std::ostream& operator<<(std::ostream& out, printable_typename<T>) {
     const char *implementation_typename = typeid(T).name();
 #ifdef __GNUC__
     int status;
-    const char* pretty_name =
+    char* pretty_name =
         abi::__cxa_demangle(implementation_typename, NULL, NULL, &status);
     if (status == 0)
         out << pretty_name;
-    free((void*) pretty_name);
+    free(static_cast<void*>(pretty_name));
     if (status == 0)
         return out;
 #endif
diff --git a/include/pcg_random.hpp b/include/pcg_random.hpp
index 59bc480..4550b3f 100644
--- a/include/pcg_random.hpp
+++ b/include/pcg_random.hpp
@@ -75,6 +75,7 @@
 #ifndef PCG_RAND_HPP_INCLUDED
 #define PCG_RAND_HPP_INCLUDED 1
 
+#include <algorithm>
 #include <cinttypes>
 #include <cstddef>
 #include <cstdlib>
@@ -82,6 +83,7 @@
 #include <cassert>
 #include <limits>
 #include <iostream>
+#include <iterator>
 #include <type_traits>
 #include <utility>
 #include <locale>
@@ -321,7 +323,7 @@ class specific_stream {
     specific_stream() = default;
 
     specific_stream(itype specific_seq)
-        : inc_((specific_seq << 1) | itype(1U))
+        : inc_(itype(specific_seq << 1) | itype(1U))
     {
         // Nothing (else) to do.
     }
@@ -380,7 +382,7 @@ class engine : protected output_mixin,
 
     static constexpr result_type max()
     {
-        return ~result_type(0UL);
+        return result_type(~result_type(0UL));
     }
 
 protected:
@@ -422,7 +424,7 @@ class engine : protected output_mixin,
     static itype distance(itype cur_state, itype newstate, itype cur_mult,
                           itype cur_plus, itype mask = ~itype(0U));
 
-    itype distance(itype newstate, itype mask = ~itype(0U)) const
+    itype distance(itype newstate, itype mask = itype(~itype(0U))) const
     {
         return distance(state_, newstate, multiplier(), increment(), mask);
     }
@@ -1360,7 +1362,10 @@ bool operator==(const extended<table_pow2, advance_pow2,
     auto& base_lhs = static_cast<const baseclass&>(lhs);
     auto& base_rhs = static_cast<const baseclass&>(rhs);
     return base_lhs == base_rhs
-        && !memcmp((void*) lhs.data_, (void*) rhs.data_, sizeof(lhs.data_));
+        && !std::equal(
+                std::begin(lhs.data_), std::end(lhs.data_),
+                std::begin(rhs.data_)
+            );
 }
 
 template <bitcount_t table_pow2, bitcount_t advance_pow2,
diff --git a/test-high/Makefile b/test-high/Makefile
index 48ff6d5..3d11c2f 100644
--- a/test-high/Makefile
+++ b/test-high/Makefile
@@ -38,7 +38,16 @@ TARGETS           = \
     check-pcg64_oneseq check-pcg64_oneseq_once_insecure check-pcg64_unique \
     check-pcg128_once_insecure check-pcg128_oneseq_once_insecure
 
-CPPFLAGS += -I../include 
+# special flags for some compilers
+CPPFLAGS_clang++ += \
+	-Weverything \
+	-Wno-c++98-compat \
+	-Wno-c++98-compat-pedantic \
+	-Wno-date-time \
+	-Wno-undef \
+	-Wno-unused-macros
+
+CPPFLAGS += -I../include -Wall -Wextra $(CPPFLAGS_$(CXX))
 CXXFLAGS += -std=c++11
 CC       = $(CXX)       # Cheat so that linking uses the C++ compiler
 
diff --git a/test-high/pcg-test-noadvance.cpp b/test-high/pcg-test-noadvance.cpp
index 4e43b67..61c414d 100644
--- a/test-high/pcg-test-noadvance.cpp
+++ b/test-high/pcg-test-noadvance.cpp
@@ -126,7 +126,6 @@ int main(int argc, char** argv)
             cout << (rng(2) ? "H" : "T");
         cout << endl;
 
-        RNG rng_copy{rng};
         /* Roll some dice */
         printf("  Rolls:");
         for (int i = 0; i < 33; ++i)