diff --git a/CMakeLists.txt b/CMakeLists.txt
index 000817d..d1e3d44 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,6 +24,8 @@ set(SOURCES
   src/ctype/charprops.c
   src/ctype/classes.c
   src/ctype/convert.c
+  # stdlib
+  src/stdlib/arith.c
   # string
   src/string/memarray.c
   src/string/core.c
diff --git a/include/ft/all-tests.h b/include/ft/all-tests.h
index 5540ad3..05a210e 100644
--- a/include/ft/all-tests.h
+++ b/include/ft/all-tests.h
@@ -13,6 +13,9 @@ extern ft_test ft_ctype_functions;
 extern ft_test ft_ctype_convert_macros;
 extern ft_test ft_ctype_convert_functions;
 
+/* stdlib */
+extern ft_test ft_stdlib_arith;
+
 /* string */
 extern ft_test ft_string_memset;
 extern ft_test ft_string_memcpy;
diff --git a/src/main.c b/src/main.c
index 260d64b..5e1a990 100644
--- a/src/main.c
+++ b/src/main.c
@@ -28,7 +28,10 @@ ft_list headers_libc[] = {
         { "Format types and options",  NULL, NULL },
         { NULL },
     }}, */
-    { "<stdlib.h>", NULL },
+    { "<stdlib.h>", (ft_test*[]){
+        &ft_stdlib_arith,
+        NULL,
+    }},
     { "<string.h>", (ft_test*[]){
         &ft_string_memset,
         &ft_string_memcpy,
diff --git a/src/stdlib/arith.c b/src/stdlib/arith.c
new file mode 100644
index 0000000..1b32222
--- /dev/null
+++ b/src/stdlib/arith.c
@@ -0,0 +1,64 @@
+#include <stdlib.h>
+#include <limits.h>
+#include <ft/test.h>
+#include <ft/all-tests.h>
+
+static void _ft_stdlib_arith(ft_test *t)
+{
+	div_t d;
+	ldiv_t ld;
+	lldiv_t lld;
+
+	ft_log(t, "abs with functions:\n");
+	ft_assert_eval(t, abs(73), 73, "%d");
+	ft_assert_eval(t, abs(-73), 73, "%d");
+	ft_assert_eval(t, labs(73l), 73l, "%ld");
+	ft_assert_eval(t, labs(-73l), 73l, "%ld");
+	ft_assert_eval(t, llabs(73ll), 73ll, "%lld");
+	ft_assert_eval(t, llabs(-73ll), 73ll, "%lld");
+
+	#undef abs
+	#undef labs
+	#undef llabs
+
+	ft_log(t, "\nabs with macros:\n");
+	ft_assert_eval(t, abs(73), 73, "%d");
+	ft_assert_eval(t, abs(-73), 73, "%d");
+	ft_assert_eval(t, labs(73l), 73l, "%ld");
+	ft_assert_eval(t, labs(-73l), 73l, "%ld");
+	ft_assert_eval(t, llabs(73ll), 73ll, "%lld");
+	ft_assert_eval(t, llabs(-73ll), 73ll, "%lld");
+
+	ft_log(t, "\ndiv: by asserts (not shown)\n");
+	d = div(73, 8);
+	ft_assert(t, d.quot == 9 && d.rem == 1);
+	d = div(-73, 8);
+	ft_assert(t, d.quot == -9 && d.rem == -1);
+	d = div(73, -8);
+	ft_assert(t, d.quot == -9 && d.rem == 1);
+	d = div(-73, -8);
+	ft_assert(t, d.quot == 9 && d.rem == -1);
+
+	ld = ldiv(73l, 8l);
+	ft_assert(t, ld.quot == 9l && ld.rem == 1l);
+	ld = ldiv(-73l, 8l);
+	ft_assert(t, ld.quot == -9l && ld.rem == -1l);
+	ld = ldiv(73l, -8l);
+	ft_assert(t, ld.quot == -9l && ld.rem == 1l);
+	ld = ldiv(-73l, -8l);
+	ft_assert(t, ld.quot == 9l && ld.rem == -1l);
+
+	lld = lldiv(73ll, 8ll);
+	ft_assert(t, lld.quot == 9ll && lld.rem == 1ll);
+	lld = lldiv(-73ll, 8ll);
+	ft_assert(t, lld.quot == -9ll && lld.rem == -1ll);
+	lld = lldiv(73ll, -8ll);
+	ft_assert(t, lld.quot == -9ll && lld.rem == 1ll);
+	lld = lldiv(-73ll, -8ll);
+	ft_assert(t, lld.quot == 9ll && lld.rem == -1ll);
+}
+
+ft_test ft_stdlib_arith = {
+	.name = "Integer arithmetic functions",
+	.function = _ft_stdlib_arith,
+};