diff --git a/libc/test/src/stdlib/strtol_test.cpp b/libc/test/src/stdlib/strtol_test.cpp
--- a/libc/test/src/stdlib/strtol_test.cpp
+++ b/libc/test/src/stdlib/strtol_test.cpp
@@ -12,6 +12,7 @@
 
 #include <errno.h>
 #include <limits.h>
+#include <stddef.h>
 
 TEST(LlvmLibcStrToLTest, InvalidBase) {
   const char *ten = "10";
@@ -27,7 +28,8 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(ten, &str_end, 10), 10l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - ten, 2l);
+  EXPECT_EQ(str_end - ten, ptrdiff_t(2));
+
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(ten, nullptr, 10), 10l);
   ASSERT_EQ(errno, 0);
@@ -36,39 +38,39 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(hundred, &str_end, 10), 100l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - hundred, 3l);
+  EXPECT_EQ(str_end - hundred, ptrdiff_t(3));
 
   const char *negative = "-100";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(negative, &str_end, 10), -100l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - negative, 4l);
+  EXPECT_EQ(str_end - negative, ptrdiff_t(4));
 
   const char *big_number = "123456789012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(big_number, &str_end, 10), 123456789012345l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - big_number, 15l);
+  EXPECT_EQ(str_end - big_number, ptrdiff_t(15));
 
   const char *big_negative_number = "-123456789012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(big_negative_number, &str_end, 10),
             -123456789012345l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - big_negative_number, 16l);
+  EXPECT_EQ(str_end - big_negative_number, ptrdiff_t(16));
 
   const char *too_big_number = "123456789012345678901";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(too_big_number, &str_end, 10), LONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - too_big_number, 21l);
+  EXPECT_EQ(str_end - too_big_number, ptrdiff_t(21));
 
   const char *too_big_negative_number = "-123456789012345678901";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(too_big_negative_number, &str_end, 10),
             LONG_MIN);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - too_big_negative_number, 22l);
+  EXPECT_EQ(str_end - too_big_negative_number, ptrdiff_t(22));
 
   const char *long_number_range_test =
       "10000000000000000000000000000000000000000000000000";
@@ -76,7 +78,7 @@
   ASSERT_EQ(__llvm_libc::strtol(long_number_range_test, &str_end, 10),
             LONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - long_number_range_test, 50l);
+  EXPECT_EQ(str_end - long_number_range_test, ptrdiff_t(50));
 }
 
 TEST(LlvmLibcStrToLTest, MessyBaseTenDecode) {
@@ -86,61 +88,61 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(spaces_before, &str_end, 10), 10l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - spaces_before, 7l);
+  EXPECT_EQ(str_end - spaces_before, ptrdiff_t(7));
 
   const char *spaces_after = "10      ";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(spaces_after, &str_end, 10), 10l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - spaces_after, 2l);
+  EXPECT_EQ(str_end - spaces_after, ptrdiff_t(2));
 
   const char *word_before = "word10";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(word_before, &str_end, 10), 0l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - word_before, 0l);
+  EXPECT_EQ(str_end - word_before, ptrdiff_t(0));
 
   const char *word_after = "10word";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(word_after, &str_end, 10), 10l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - word_after, 2l);
+  EXPECT_EQ(str_end - word_after, ptrdiff_t(2));
 
   const char *two_numbers = "10 999";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(two_numbers, &str_end, 10), 10l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - two_numbers, 2l);
+  EXPECT_EQ(str_end - two_numbers, ptrdiff_t(2));
 
   const char *two_signs = "--10 999";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(two_signs, &str_end, 10), 0l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - two_signs, 1l);
+  EXPECT_EQ(str_end - two_signs, ptrdiff_t(1));
 
   const char *sign_before = "+2=4";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(sign_before, &str_end, 10), 2l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - sign_before, 2l);
+  EXPECT_EQ(str_end - sign_before, ptrdiff_t(2));
 
   const char *sign_after = "2+2=4";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(sign_after, &str_end, 10), 2l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - sign_after, 1l);
+  EXPECT_EQ(str_end - sign_after, ptrdiff_t(1));
 
   const char *tab_before = "\t10";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(tab_before, &str_end, 10), 10l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - tab_before, 3l);
+  EXPECT_EQ(str_end - tab_before, ptrdiff_t(3));
 
   const char *all_together = "\t  -12345and+67890";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(all_together, &str_end, 10), -12345l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - all_together, 9l);
+  EXPECT_EQ(str_end - all_together, ptrdiff_t(9));
 }
 
 static char int_to_b36_char(int input) {
@@ -250,13 +252,13 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(no_prefix, &str_end, 16), 0x123abcl);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - no_prefix, 6l);
+  EXPECT_EQ(str_end - no_prefix, ptrdiff_t(6));
 
   const char *yes_prefix = "0x456def";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(yes_prefix, &str_end, 16), 0x456defl);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - yes_prefix, 8l);
+  EXPECT_EQ(str_end - yes_prefix, ptrdiff_t(8));
 }
 
 TEST(LlvmLibcStrToLTest, AutomaticBaseSelection) {
@@ -266,24 +268,24 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(base_ten, &str_end, 0), 12345l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_ten, 5l);
+  EXPECT_EQ(str_end - base_ten, ptrdiff_t(5));
 
   const char *base_sixteen_no_prefix = "123abc";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(base_sixteen_no_prefix, &str_end, 0), 123l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_sixteen_no_prefix, 3l);
+  EXPECT_EQ(str_end - base_sixteen_no_prefix, ptrdiff_t(3));
 
   const char *base_sixteen_with_prefix = "0x456def";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(base_sixteen_with_prefix, &str_end, 0),
             0x456defl);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_sixteen_with_prefix, 8l);
+  EXPECT_EQ(str_end - base_sixteen_with_prefix, ptrdiff_t(8));
 
   const char *base_eight_with_prefix = "012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtol(base_eight_with_prefix, &str_end, 0), 012345l);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_eight_with_prefix, 6l);
+  EXPECT_EQ(str_end - base_eight_with_prefix, ptrdiff_t(6));
 }
diff --git a/libc/test/src/stdlib/strtoll_test.cpp b/libc/test/src/stdlib/strtoll_test.cpp
--- a/libc/test/src/stdlib/strtoll_test.cpp
+++ b/libc/test/src/stdlib/strtoll_test.cpp
@@ -12,6 +12,7 @@
 
 #include <errno.h>
 #include <limits.h>
+#include <stddef.h>
 
 TEST(LlvmLibcStrToLLTest, InvalidBase) {
   const char *ten = "10";
@@ -27,7 +28,7 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(ten, &str_end, 10), 10ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - ten, 2l);
+  EXPECT_EQ(str_end - ten, ptrdiff_t(2));
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(ten, nullptr, 10), 10ll);
   ASSERT_EQ(errno, 0);
@@ -36,53 +37,53 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(hundred, &str_end, 10), 100ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - hundred, 3l);
+  EXPECT_EQ(str_end - hundred, ptrdiff_t(3));
 
   const char *negative = "-100";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(negative, &str_end, 10), -100ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - negative, 4l);
+  EXPECT_EQ(str_end - negative, ptrdiff_t(4));
 
   const char *big_number = "123456789012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(big_number, &str_end, 10), 123456789012345ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - big_number, 15l);
+  EXPECT_EQ(str_end - big_number, ptrdiff_t(15));
 
   const char *big_negative_number = "-123456789012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(big_negative_number, &str_end, 10),
             -123456789012345ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - big_negative_number, 16l);
+  EXPECT_EQ(str_end - big_negative_number, ptrdiff_t(16));
 
   const char *long_long_max_number = "9223372036854775807";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(long_long_max_number, &str_end, 10),
             9223372036854775807ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - long_long_max_number, 19l);
+  EXPECT_EQ(str_end - long_long_max_number, ptrdiff_t(19));
 
   const char *long_long_min_number = "-9223372036854775808";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(long_long_min_number, &str_end, 10),
             -9223372036854775807ll - 1ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - long_long_min_number, 20l);
+  EXPECT_EQ(str_end - long_long_min_number, ptrdiff_t(20));
 
   const char *too_big_number = "123456789012345678901";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(too_big_number, &str_end, 10), LLONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - too_big_number, 21l);
+  EXPECT_EQ(str_end - too_big_number, ptrdiff_t(21));
 
   const char *too_big_negative_number = "-123456789012345678901";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(too_big_negative_number, &str_end, 10),
             LLONG_MIN);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - too_big_negative_number, 22l);
+  EXPECT_EQ(str_end - too_big_negative_number, ptrdiff_t(22));
 
   const char *long_number_range_test =
       "10000000000000000000000000000000000000000000000000";
@@ -90,7 +91,7 @@
   ASSERT_EQ(__llvm_libc::strtoll(long_number_range_test, &str_end, 10),
             LLONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - long_number_range_test, 50l);
+  EXPECT_EQ(str_end - long_number_range_test, ptrdiff_t(50));
 
   const char *long_long_max_number_with_numbers_after =
       "9223372036854775807123";
@@ -99,7 +100,9 @@
                                  &str_end, 10),
             LLONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - long_long_max_number_with_numbers_after, 22l);
+  EXPECT_EQ(
+      static_cast<long long>(str_end - long_long_max_number_with_numbers_after),
+      22ll);
 }
 
 TEST(LlvmLibcStrToLLTest, MessyBaseTenDecode) {
@@ -109,61 +112,61 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(spaces_before, &str_end, 10), 10ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - spaces_before, 7l);
+  EXPECT_EQ(str_end - spaces_before, ptrdiff_t(7));
 
   const char *spaces_after = "10      ";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(spaces_after, &str_end, 10), 10ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - spaces_after, 2l);
+  EXPECT_EQ(str_end - spaces_after, ptrdiff_t(2));
 
   const char *word_before = "word10";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(word_before, &str_end, 10), 0ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - word_before, 0l);
+  EXPECT_EQ(str_end - word_before, ptrdiff_t(0));
 
   const char *word_after = "10word";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(word_after, &str_end, 10), 10ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - word_after, 2l);
+  EXPECT_EQ(str_end - word_after, ptrdiff_t(2));
 
   const char *two_numbers = "10 999";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(two_numbers, &str_end, 10), 10ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - two_numbers, 2l);
+  EXPECT_EQ(str_end - two_numbers, ptrdiff_t(2));
 
   const char *two_signs = "--10 999";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(two_signs, &str_end, 10), 0ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - two_signs, 1l);
+  EXPECT_EQ(str_end - two_signs, ptrdiff_t(1));
 
   const char *sign_before = "+2=4";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(sign_before, &str_end, 10), 2ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - sign_before, 2l);
+  EXPECT_EQ(str_end - sign_before, ptrdiff_t(2));
 
   const char *sign_after = "2+2=4";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(sign_after, &str_end, 10), 2ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - sign_after, 1l);
+  EXPECT_EQ(str_end - sign_after, ptrdiff_t(1));
 
   const char *tab_before = "\t10";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(tab_before, &str_end, 10), 10ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - tab_before, 3l);
+  EXPECT_EQ(str_end - tab_before, ptrdiff_t(3));
 
   const char *all_together = "\t  -12345and+67890";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(all_together, &str_end, 10), -12345ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - all_together, 9l);
+  EXPECT_EQ(str_end - all_together, ptrdiff_t(9));
 }
 
 static char int_to_b36_char(int input) {
@@ -274,13 +277,13 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(no_prefix, &str_end, 16), 0x123abcll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - no_prefix, 6l);
+  EXPECT_EQ(str_end - no_prefix, ptrdiff_t(6));
 
   const char *yes_prefix = "0x456def";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(yes_prefix, &str_end, 16), 0x456defll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - yes_prefix, 8l);
+  EXPECT_EQ(str_end - yes_prefix, ptrdiff_t(8));
 }
 
 TEST(LlvmLibcStrToLLTest, AutomaticBaseSelection) {
@@ -290,25 +293,25 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(base_ten, &str_end, 0), 12345ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_ten, 5l);
+  EXPECT_EQ(str_end - base_ten, ptrdiff_t(5));
 
   const char *base_sixteen_no_prefix = "123abc";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(base_sixteen_no_prefix, &str_end, 0), 123ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_sixteen_no_prefix, 3l);
+  EXPECT_EQ(str_end - base_sixteen_no_prefix, ptrdiff_t(3));
 
   const char *base_sixteen_with_prefix = "0x456def";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(base_sixteen_with_prefix, &str_end, 0),
             0x456defll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_sixteen_with_prefix, 8l);
+  EXPECT_EQ(str_end - base_sixteen_with_prefix, ptrdiff_t(8));
 
   const char *base_eight_with_prefix = "012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoll(base_eight_with_prefix, &str_end, 0),
             012345ll);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_eight_with_prefix, 6l);
+  EXPECT_EQ(str_end - base_eight_with_prefix, ptrdiff_t(6));
 }
diff --git a/libc/test/src/stdlib/strtoul_test.cpp b/libc/test/src/stdlib/strtoul_test.cpp
--- a/libc/test/src/stdlib/strtoul_test.cpp
+++ b/libc/test/src/stdlib/strtoul_test.cpp
@@ -12,6 +12,7 @@
 
 #include <errno.h>
 #include <limits.h>
+#include <stddef.h>
 
 TEST(LlvmLibcStrToULTest, InvalidBase) {
   const char *ten = "10";
@@ -27,7 +28,7 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(ten, &str_end, 10), 10ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - ten, 2l);
+  EXPECT_EQ(str_end - ten, ptrdiff_t(2));
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(ten, nullptr, 10), 10ul);
   ASSERT_EQ(errno, 0);
@@ -36,32 +37,32 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(hundred, &str_end, 10), 100ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - hundred, 3l);
+  EXPECT_EQ(str_end - hundred, ptrdiff_t(3));
 
   const char *negative = "-100";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(negative, &str_end, 10), -(100ul));
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - negative, 4l);
+  EXPECT_EQ(str_end - negative, ptrdiff_t(4));
 
   const char *big_number = "123456789012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(big_number, &str_end, 10), 123456789012345ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - big_number, 15l);
+  EXPECT_EQ(str_end - big_number, ptrdiff_t(15));
 
   const char *too_big_number = "123456789012345678901";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(too_big_number, &str_end, 10), ULONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - too_big_number, 21l);
+  EXPECT_EQ(str_end - too_big_number, ptrdiff_t(21));
 
   const char *too_big_negative_number = "-123456789012345678901";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(too_big_negative_number, &str_end, 10),
             ULONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - too_big_negative_number, 22l);
+  EXPECT_EQ(str_end - too_big_negative_number, ptrdiff_t(22));
 
   const char *long_number_range_test =
       "10000000000000000000000000000000000000000000000000";
@@ -69,7 +70,7 @@
   ASSERT_EQ(__llvm_libc::strtoul(long_number_range_test, &str_end, 10),
             ULONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - long_number_range_test, 50l);
+  EXPECT_EQ(str_end - long_number_range_test, ptrdiff_t(50));
 }
 
 TEST(LlvmLibcStrToULTest, MessyBaseTenDecode) {
@@ -79,61 +80,61 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(spaces_before, &str_end, 10), 10ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - spaces_before, 7l);
+  EXPECT_EQ(str_end - spaces_before, ptrdiff_t(7));
 
   const char *spaces_after = "10      ";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(spaces_after, &str_end, 10), 10ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - spaces_after, 2l);
+  EXPECT_EQ(str_end - spaces_after, ptrdiff_t(2));
 
   const char *word_before = "word10";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(word_before, &str_end, 10), 0ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - word_before, 0l);
+  EXPECT_EQ(str_end - word_before, ptrdiff_t(0));
 
   const char *word_after = "10word";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(word_after, &str_end, 10), 10ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - word_after, 2l);
+  EXPECT_EQ(str_end - word_after, ptrdiff_t(2));
 
   const char *two_numbers = "10 999";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(two_numbers, &str_end, 10), 10ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - two_numbers, 2l);
+  EXPECT_EQ(str_end - two_numbers, ptrdiff_t(2));
 
   const char *two_signs = "--10 999";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(two_signs, &str_end, 10), 0ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - two_signs, 1l);
+  EXPECT_EQ(str_end - two_signs, ptrdiff_t(1));
 
   const char *sign_before = "+2=4";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(sign_before, &str_end, 10), 2ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - sign_before, 2l);
+  EXPECT_EQ(str_end - sign_before, ptrdiff_t(2));
 
   const char *sign_after = "2+2=4";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(sign_after, &str_end, 10), 2ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - sign_after, 1l);
+  EXPECT_EQ(str_end - sign_after, ptrdiff_t(1));
 
   const char *tab_before = "\t10";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(tab_before, &str_end, 10), 10ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - tab_before, 3l);
+  EXPECT_EQ(str_end - tab_before, ptrdiff_t(3));
 
   const char *all_together = "\t  -12345and+67890";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(all_together, &str_end, 10), -(12345ul));
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - all_together, 9l);
+  EXPECT_EQ(str_end - all_together, ptrdiff_t(9));
 }
 
 static char int_to_b36_char(int input) {
@@ -244,13 +245,13 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(no_prefix, &str_end, 16), 0x123abcul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - no_prefix, 6l);
+  EXPECT_EQ(str_end - no_prefix, ptrdiff_t(6));
 
   const char *yes_prefix = "0x456def";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(yes_prefix, &str_end, 16), 0x456deful);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - yes_prefix, 8l);
+  EXPECT_EQ(str_end - yes_prefix, ptrdiff_t(8));
 }
 
 TEST(LlvmLibcStrToULTest, AutomaticBaseSelection) {
@@ -260,25 +261,25 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(base_ten, &str_end, 0), 12345ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_ten, 5l);
+  EXPECT_EQ(str_end - base_ten, ptrdiff_t(5));
 
   const char *base_sixteen_no_prefix = "123abc";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(base_sixteen_no_prefix, &str_end, 0), 123ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_sixteen_no_prefix, 3l);
+  EXPECT_EQ(str_end - base_sixteen_no_prefix, ptrdiff_t(3));
 
   const char *base_sixteen_with_prefix = "0x456def";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(base_sixteen_with_prefix, &str_end, 0),
             0x456deful);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_sixteen_with_prefix, 8l);
+  EXPECT_EQ(str_end - base_sixteen_with_prefix, ptrdiff_t(8));
 
   const char *base_eight_with_prefix = "012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoul(base_eight_with_prefix, &str_end, 0),
             012345ul);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_eight_with_prefix, 6l);
+  EXPECT_EQ(str_end - base_eight_with_prefix, ptrdiff_t(6));
 }
diff --git a/libc/test/src/stdlib/strtoull_test.cpp b/libc/test/src/stdlib/strtoull_test.cpp
--- a/libc/test/src/stdlib/strtoull_test.cpp
+++ b/libc/test/src/stdlib/strtoull_test.cpp
@@ -12,6 +12,7 @@
 
 #include <errno.h>
 #include <limits.h>
+#include <stddef.h>
 
 TEST(LlvmLibcStrToULLTest, InvalidBase) {
   const char *ten = "10";
@@ -27,7 +28,7 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(ten, &str_end, 10), 10ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - ten, 2l);
+  EXPECT_EQ(str_end - ten, ptrdiff_t(2));
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(ten, nullptr, 10), 10ull);
   ASSERT_EQ(errno, 0);
@@ -36,40 +37,40 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(hundred, &str_end, 10), 100ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - hundred, 3l);
+  EXPECT_EQ(str_end - hundred, ptrdiff_t(3));
 
   const char *negative = "-100";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(negative, &str_end, 10), -(100ull));
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - negative, 4l);
+  EXPECT_EQ(str_end - negative, ptrdiff_t(4));
 
   const char *big_number = "123456789012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(big_number, &str_end, 10),
             123456789012345ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - big_number, 15l);
+  EXPECT_EQ(str_end - big_number, ptrdiff_t(15));
 
   const char *unsigned_long_long_max_number = "18446744073709551615";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(unsigned_long_long_max_number, &str_end, 10),
             18446744073709551615ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - unsigned_long_long_max_number, 20l);
+  EXPECT_EQ(str_end - unsigned_long_long_max_number, ptrdiff_t(20));
 
   const char *too_big_number = "123456789012345678901";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(too_big_number, &str_end, 10), ULLONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - too_big_number, 21l);
+  EXPECT_EQ(str_end - too_big_number, ptrdiff_t(21));
 
   const char *too_big_negative_number = "-123456789012345678901";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(too_big_negative_number, &str_end, 10),
             ULLONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - too_big_negative_number, 22l);
+  EXPECT_EQ(str_end - too_big_negative_number, ptrdiff_t(22));
 
   const char *long_number_range_test =
       "10000000000000000000000000000000000000000000000000";
@@ -77,7 +78,7 @@
   ASSERT_EQ(__llvm_libc::strtoull(long_number_range_test, &str_end, 10),
             ULLONG_MAX);
   ASSERT_EQ(errno, ERANGE);
-  EXPECT_EQ(str_end - long_number_range_test, 50l);
+  EXPECT_EQ(str_end - long_number_range_test, ptrdiff_t(50));
 }
 
 TEST(LlvmLibcStrToULLTest, MessyBaseTenDecode) {
@@ -87,61 +88,61 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(spaces_before, &str_end, 10), 10ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - spaces_before, 7l);
+  EXPECT_EQ(str_end - spaces_before, ptrdiff_t(7));
 
   const char *spaces_after = "10      ";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(spaces_after, &str_end, 10), 10ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - spaces_after, 2l);
+  EXPECT_EQ(str_end - spaces_after, ptrdiff_t(2));
 
   const char *word_before = "word10";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(word_before, &str_end, 10), 0ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - word_before, 0l);
+  EXPECT_EQ(str_end - word_before, ptrdiff_t(0));
 
   const char *word_after = "10word";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(word_after, &str_end, 10), 10ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - word_after, 2l);
+  EXPECT_EQ(str_end - word_after, ptrdiff_t(2));
 
   const char *two_numbers = "10 999";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(two_numbers, &str_end, 10), 10ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - two_numbers, 2l);
+  EXPECT_EQ(str_end - two_numbers, ptrdiff_t(2));
 
   const char *two_signs = "--10 999";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(two_signs, &str_end, 10), 0ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - two_signs, 1l);
+  EXPECT_EQ(str_end - two_signs, ptrdiff_t(1));
 
   const char *sign_before = "+2=4";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(sign_before, &str_end, 10), 2ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - sign_before, 2l);
+  EXPECT_EQ(str_end - sign_before, ptrdiff_t(2));
 
   const char *sign_after = "2+2=4";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(sign_after, &str_end, 10), 2ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - sign_after, 1l);
+  EXPECT_EQ(str_end - sign_after, ptrdiff_t(1));
 
   const char *tab_before = "\t10";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(tab_before, &str_end, 10), 10ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - tab_before, 3l);
+  EXPECT_EQ(str_end - tab_before, ptrdiff_t(3));
 
   const char *all_together = "\t  -12345and+67890";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(all_together, &str_end, 10), -(12345ull));
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - all_together, 9l);
+  EXPECT_EQ(str_end - all_together, ptrdiff_t(9));
 }
 
 static char int_to_b36_char(int input) {
@@ -255,13 +256,13 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(no_prefix, &str_end, 16), 0x123abcull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - no_prefix, 6l);
+  EXPECT_EQ(str_end - no_prefix, ptrdiff_t(6));
 
   const char *yes_prefix = "0x456def";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(yes_prefix, &str_end, 16), 0x456defull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - yes_prefix, 8l);
+  EXPECT_EQ(str_end - yes_prefix, ptrdiff_t(8));
 }
 
 TEST(LlvmLibcStrToULLTest, AutomaticBaseSelection) {
@@ -271,25 +272,25 @@
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(base_ten, &str_end, 0), 12345ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_ten, 5l);
+  EXPECT_EQ(str_end - base_ten, ptrdiff_t(5));
 
   const char *base_sixteen_no_prefix = "123abc";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(base_sixteen_no_prefix, &str_end, 0), 123ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_sixteen_no_prefix, 3l);
+  EXPECT_EQ(str_end - base_sixteen_no_prefix, ptrdiff_t(3));
 
   const char *base_sixteen_with_prefix = "0x456def";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(base_sixteen_with_prefix, &str_end, 0),
             0x456defull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_sixteen_with_prefix, 8l);
+  EXPECT_EQ(str_end - base_sixteen_with_prefix, ptrdiff_t(8));
 
   const char *base_eight_with_prefix = "012345";
   errno = 0;
   ASSERT_EQ(__llvm_libc::strtoull(base_eight_with_prefix, &str_end, 0),
             012345ull);
   ASSERT_EQ(errno, 0);
-  EXPECT_EQ(str_end - base_eight_with_prefix, 6l);
+  EXPECT_EQ(str_end - base_eight_with_prefix, ptrdiff_t(6));
 }
diff --git a/libc/utils/CPP/Limits.h b/libc/utils/CPP/Limits.h
--- a/libc/utils/CPP/Limits.h
+++ b/libc/utils/CPP/Limits.h
@@ -39,8 +39,8 @@
 };
 template <> class NumericLimits<unsigned long> {
 public:
-  static constexpr long max() { return ULONG_MAX; }
-  static constexpr long min() { return 0; }
+  static constexpr unsigned long max() { return ULONG_MAX; }
+  static constexpr unsigned long min() { return 0; }
 };
 template <> class NumericLimits<long long> {
 public:
@@ -49,8 +49,8 @@
 };
 template <> class NumericLimits<unsigned long long> {
 public:
-  static constexpr long max() { return ULLONG_MAX; }
-  static constexpr long min() { return 0; }
+  static constexpr unsigned long long max() { return ULLONG_MAX; }
+  static constexpr unsigned long long min() { return 0; }
 };
 
 } // namespace cpp