diff -Nur package/bla/Makefile package/roundf/Makefile
--- package/bla/Makefile	1970-01-01 01:00:00.000000000 +0100
+++ package/roundf/Makefile	2007-10-06 02:44:00.000000000 +0200
@@ -0,0 +1,38 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=roundf
+PKG_VERSION:=0.0.0
+PKG_RELEASE:=1
+
+PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(PKG_VERSION)
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/roundf
+  SECTION:=utils
+  CATEGORY:=Utilities
+  TITLE:=just some code for testing if roundf is there and working
+  DEPENDS:=
+  DESCRIPTION:=see title
+  URL:=
+  VERSION:=1
+endef
+
+define Build/Prepare
+	mkdir -p $(PKG_BUILD_DIR)
+	$(CP) ./src/* $(PKG_BUILD_DIR)/
+endef
+
+define Build/Compile
+	$(MAKE) -C $(PKG_BUILD_DIR) \
+		$(TARGET_CONFIGURE_OPTS) \
+		CFLAGS="$(TARGET_CFLAGS)" \
+		LDFLAGS="-lm"
+endef
+
+define Package/roundf/install
+	$(INSTALL_DIR) $(1)/sbin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/roundf-test $(1)/sbin/
+endef
+
+$(eval $(call BuildPackage,roundf))
diff -Nur package/bla/src/Makefile package/roundf/src/Makefile
--- package/bla/src/Makefile	1970-01-01 01:00:00.000000000 +0100
+++ package/roundf/src/Makefile	2007-10-06 02:42:13.000000000 +0200
@@ -0,0 +1,7 @@
+all: roundf-test
+
+%.o: %.c
+	$(CC) -lm -I. $(CFLAGS) $(EXTRA_CFLAGS) -c -o $@ $^
+
+clean:
+	rm -f *.o roudf-test
diff -Nur package/bla/src/roundf-test.c package/roundf/src/roundf-test.c
--- package/bla/src/roundf-test.c	1970-01-01 01:00:00.000000000 +0100
+++ package/roundf/src/roundf-test.c	2007-10-06 02:30:36.000000000 +0200
@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <math.h>
+
+int main(int argc, char** argv)
+{
+   float conv, temp;
+   scanf("%f",&temp);
+   printf("Tensao => \"%f\"\n", temp);
+   conv =  temp * (17.650862069);
+   conv = roundf(conv);
+ 
+   printf("Convertido => \"%f\"\n", conv);
+}