The module should be compiled as a object file and not as a executable. include -c flag while compiling with gcc. I hope it helps you On 9/23/05, Florin Malita <fmalita@xxxxxxxxx> wrote: > On Fri, 23 Sep 2005 19:13:50 +0530 > Panthini <panthini.pandit@xxxxxxxxxxxxxx> wrote: > > > Following is the screenshot of compilation process: > > [root@localhost root]# gcc -Wall -O2 -D__KERNEL__ -DMODULE > > -I/usr/src/linux-2.4.21-27.EL/include/ hello.c > > > > /usr/lib/gcc-lib/i386-redhat-linux/3.2.3/../../../crt1.o(.text+0x18): > > In function `_start': > > : undefined reference to `main' > > collect2: ld returned 1 exit status > > [root@localhost root]# > > /***************************************/ > > why this is referring to 'main' even though I have not written any > > main() function in hello.c. > > gcc automatically links agains libc & libgcc unless instructed not to > do it (-nostdlib). Alternatively, you could link with ld instead of gcc. > > But building modules that way (with your own compiler command line & > options) is strongly discouraged. You should use the kernel build > system even when building external modules. See > http://lwn.net/Articles/21823/ for details, most of it applies to > recent 2.4 kernels too. > > Here's a simple makefile that works for me on AS 3.0: > > > ######################################### > > O_TARGET := hello_module.o > > obj-y := hello.o > > obj-m := $(O_TARGET) > > include $(TOPDIR)/Rules.make > > ######################################### > > Then you can build with the following command: > > make -C /lib/modules/`uname -r`/build modules SUBDIRS=`pwd` > > -- > Kernelnewbies: Help each other learn about the Linux kernel. > Archive: http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
