tests/thread_float: improve console output

Give the three threads the names "t1", "t2", and "t3" and print them
on console, instead of the process ID. This makes interpretation of
the output easier, as the process IDs depend e.g. on whether a given
platforms requires an idle thread or not.

tests/thread_float/main.c

@@ -46,11 +46,9 @@ static void timer_cb(void *arg)
 
 static void *thread1(void *arg)
 {
-    (void) arg;
-
     float f, init;
 
-    printf("THREAD %" PRIkernel_pid " start\n", thread_getpid());
+    printf("THREAD %s start\n", (const char *)arg);
 
     init = 1.0 * thread_getpid();
     f = init;
@@ -60,7 +58,7 @@ static void *thread1(void *arg)
             f = f + 1.0 / f;
         }
         mutex_lock(&lock);
-        printf("T(%" PRIkernel_pid "): %f\n", thread_getpid(), (double)f);
+        printf("%s: %f\n", (const char *)arg, (double)f);
         mutex_unlock(&lock);
         init += 1.0;
         f = init;
@@ -70,11 +68,9 @@ static void *thread1(void *arg)
 
 static void *thread2(void *arg)
 {
-    (void) arg;
-
     float f, init;
 
-    printf("THREAD %" PRIkernel_pid " start\n", thread_getpid());
+    printf("THREAD %s start\n", (const char *)arg);
 
     init = 1.0 * thread_getpid();
     f = init;
@@ -91,15 +87,18 @@ static void *thread2(void *arg)
 
 int main(void)
 {
+    const char *t1_name = "t1";
+    const char *t2_name = "t2";
+    const char *t3_name = "t3";
     p1 = thread_create(t1_stack, sizeof(t1_stack), THREAD_PRIORITY_MAIN + 1,
                        THREAD_CREATE_WOUT_YIELD | THREAD_CREATE_STACKTEST,
-                       thread1, NULL, "nr1");
+                       thread1, (void *)t1_name, t1_name);
     p2 = thread_create(t2_stack, sizeof(t2_stack), THREAD_PRIORITY_MAIN + 1,
                        THREAD_CREATE_WOUT_YIELD | THREAD_CREATE_STACKTEST,
-                       thread2, NULL, "nr2");
+                       thread2, (void *)t2_name, t2_name);
     p3 = thread_create(t3_stack, sizeof(t3_stack), THREAD_PRIORITY_MAIN + 1,
                        THREAD_CREATE_WOUT_YIELD | THREAD_CREATE_STACKTEST,
-                       thread1, NULL, "nr3");
+                       thread1, (void *)t3_name, t3_name);
     puts("THREADS CREATED\n");
 
     timer.callback = timer_cb;