diff --git a/libc/fmt/strtol.c b/libc/fmt/strtol.c
index 00b13f96d..f0892fbfa 100644
--- a/libc/fmt/strtol.c
+++ b/libc/fmt/strtol.c
@@ -17,6 +17,7 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/fmt/conv.h"
+#include "libc/errno.h"
 #include "libc/limits.h"
 
 /**
@@ -25,5 +26,15 @@
  * @param optional_base is recommended as 0 for flexidecimal
  */
 long strtol(const char *s, char **opt_out_end, int optional_base) {
-  return strtoimax(s, opt_out_end, optional_base);
+  intmax_t res;
+  res = strtoimax(s, opt_out_end, optional_base);
+  if (res < LONG_MIN) {
+    errno = ERANGE;
+    return LONG_MIN;
+  }
+  if (res > LONG_MAX) {
+    errno = ERANGE;
+    return LONG_MAX;
+  }
+  return res;
 }
diff --git a/libc/fmt/strtoll.c b/libc/fmt/strtoll.c
index bf65c7c4b..2ed524c15 100644
--- a/libc/fmt/strtoll.c
+++ b/libc/fmt/strtoll.c
@@ -17,12 +17,19 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/fmt/conv.h"
+#include "libc/errno.h"
 #include "libc/limits.h"
 
 long long strtoll(const char *s, char **endptr, int optional_base) {
-  long long res;
+  intmax_t res;
   res = strtoimax(s, endptr, optional_base);
-  if (res < LONG_LONG_MIN) return LONG_LONG_MIN;
-  if (res > LONG_LONG_MAX) return LONG_LONG_MAX;
+  if (res < LONG_LONG_MIN) {
+    errno = ERANGE;
+    return LONG_LONG_MIN;
+  }
+  if (res > LONG_LONG_MAX) {
+    errno = ERANGE;
+    return LONG_LONG_MAX;
+  }
   return res;
 }
diff --git a/libc/fmt/strtoul.c b/libc/fmt/strtoul.c
index 430a4a2b1..1e9ef3a41 100644
--- a/libc/fmt/strtoul.c
+++ b/libc/fmt/strtoul.c
@@ -17,12 +17,19 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/fmt/conv.h"
+#include "libc/errno.h"
 #include "libc/limits.h"
 
 unsigned long strtoul(const char *s, char **endptr, int optional_base) {
-  unsigned long long res;
+  intmax_t res;
   res = strtoimax(s, endptr, optional_base);
-  if (res < ULONG_MIN) return ULONG_MIN;
-  if (res > ULONG_MAX) return ULONG_MAX;
+  if (res < ULONG_MIN) {
+    errno = ERANGE;
+    return ULONG_MIN;
+  }
+  if (res > ULONG_MAX) {
+    errno = ERANGE;
+    return ULONG_MAX;
+  }
   return res;
 }
diff --git a/libc/fmt/strtoull.c b/libc/fmt/strtoull.c
index b3a3d7d17..94d4c3071 100644
--- a/libc/fmt/strtoull.c
+++ b/libc/fmt/strtoull.c
@@ -17,12 +17,19 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/fmt/conv.h"
+#include "libc/errno.h"
 #include "libc/limits.h"
 
 unsigned long long strtoull(const char *s, char **endptr, int optional_base) {
-  unsigned long long res;
+  intmax_t res;
   res = strtoimax(s, endptr, optional_base);
-  if (res < ULONG_LONG_MIN) return ULONG_LONG_MIN;
-  if (res > ULONG_LONG_MAX) return ULONG_LONG_MAX;
+  if (res < ULONG_LONG_MIN) {
+    errno = ERANGE;
+    return ULONG_LONG_MIN;
+  }
+  if (res > ULONG_LONG_MAX) {
+    errno = ERANGE;
+    return ULONG_LONG_MAX;
+  }
   return res;
 }
diff --git a/test/libc/fmt/strtoimax_test.c b/test/libc/fmt/strtoimax_test.c
index 29186a816..df22d7f94 100644
--- a/test/libc/fmt/strtoimax_test.c
+++ b/test/libc/fmt/strtoimax_test.c
@@ -19,6 +19,7 @@
 #include "libc/bits/bits.h"
 #include "libc/fmt/conv.h"
 #include "libc/testlib/testlib.h"
+#include "libc/errno.h"
 
 TEST(strtoimax, testZero) {
   EXPECT_EQ(0, strtoimax("0", NULL, 0));
@@ -57,6 +58,17 @@ TEST(strtoimax, testTwosBane) {
             strtoimax("0x80000000000000000000000000000000", NULL, 0));
 }
 
-TEST(strtol, neghex) {
-  ASSERT_EQ(-16, strtol("0xfffffffffffffff0", NULL, 0));
+TEST(strtoul, neghex) {
+  errno = 0;
+  ASSERT_EQ(-16, (long) strtoul("0xfffffffffffffff0", NULL, 0));
+  EXPECT_EQ(0, errno);
+}
+
+TEST(strtol, testOutsideLimit) {
+  errno = 0;
+  EXPECT_EQ(0x7fffffffffffffff, strtol("0x8000000000000000", NULL, 0));
+  EXPECT_EQ(ERANGE, errno);
+  errno = 0;
+  EXPECT_EQ(0x8000000000000000, strtol("-0x8000000000000001", NULL, 0));
+  EXPECT_EQ(ERANGE, errno);
 }
diff --git a/third_party/chibicc/as.c b/third_party/chibicc/as.c
index ce33af3b4..8d59d04a6 100644
--- a/third_party/chibicc/as.c
+++ b/third_party/chibicc/as.c
@@ -782,7 +782,7 @@ static void Tokenize(struct As *a, int path) {
         a->things.p[a->things.n - 1].t = TT_FLOAT;
       } else {
         APPEND(a->ints);
-        a->ints.p[a->ints.n - 1] = strtol(p, NULL, 0);
+        a->ints.p[a->ints.n - 1] = strtoul(p, NULL, 0);
         a->things.p[a->things.n - 1].i = a->ints.n - 1;
         if (p[i] == 'f' || p[i] == 'F') {
           a->things.p[a->things.n - 1].t = TT_FORWARD;