diff --git a/src/libc/stdlib/stdlib_p.h b/src/libc/stdlib/stdlib_p.h
index 1190863..f4a8288 100644
--- a/src/libc/stdlib/stdlib_p.h
+++ b/src/libc/stdlib/stdlib_p.h
@@ -15,7 +15,7 @@
    (depending on use_unsigned). Signedness only affects the range of values
    that are considered to be ERANGE, and both results are stored in *outl.
    Similarly, if outll is non-NULL, strto_int produces a long long or unsigned
-   long long result.
+   long long result. Only one pointer should be non-NULL.
 
    On platforms where long is 32-bit, 64-bit operations are performed only if
    outll is non-NULL. This is because multiplications with overflow can be
diff --git a/src/libc/stdlib/strto_int.c b/src/libc/stdlib/strto_int.c
index 5c6abd8..ae4c9bd 100644
--- a/src/libc/stdlib/strto_int.c
+++ b/src/libc/stdlib/strto_int.c
@@ -96,6 +96,16 @@ int strto_int(char const * restrict ptr, char ** restrict endptr, int base,
 			errno_value = ERANGE;
 	}
 
+	/* Handle overflows */
+	if(outl && errno_value == ERANGE) {
+		if(use_unsigned) xl = ULONG_MAX;
+		else xl = negative ? LONG_MIN : LONG_MAX;
+	}
+	if(outll && errno_value == ERANGE) {
+		if(use_unsigned) xll = ULLONG_MAX;
+		else xll = negative ? LLONG_MIN : LLONG_MAX;
+	}
+
 	if(outl) *outl = xl;
 	if(outll) *outll = xll;
 	if(endptr && valid) *endptr = (char *)ptr;