import RT-Thread@9217865c without bsp, libcpu and components/net

examples/libc/rand.c

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2010-11-17     Bernard      first version
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <finsh.h>
+
+int libc_rand(void)
+{
+    int i1, i2;
+    int j1, j2;
+
+    /* The C standard says that "If rand is called before any calls to
+     srand have been made, the same sequence shall be generated as
+     when srand is first called with a seed value of 1." */
+    i1 = rand();
+    i2 = rand();
+    srand(1);
+    j1 = rand();
+    j2 = rand();
+    if (i1 < 0 || i2 < 0 || j1 < 0 || j2 < 0)
+    {
+        puts("Test FAILED!");
+    }
+    if (j1 == i1 && j2 == i2)
+    {
+        puts("Test succeeded.");
+        return 0;
+    }
+    else
+    {
+        if (j1 != i1)
+            printf("%d != %d\n", j1, i1);
+        if (j2 != i2)
+            printf("%d != %d\n", j2, i2);
+        puts("Test FAILED!");
+        return 1;
+    }
+}
+FINSH_FUNCTION_EXPORT(libc_rand, rand test for libc);