2009/2/1 Shaz <shazalive@xxxxxxxxx>:
>
>
> On Sun, Feb 1, 2009 at 3:00 PM, loody <miloody@xxxxxxxxx> wrote:
>>
>> 2009/2/1 Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx>:
>> > On Saturday 31 January 2009 07:18, loody wrote:
>> >> > Dear all:
>> >> > I am porting kernel on my arm platform and I wrote a userspace
>> >> > program, hello world.
>> >> > But I cannot see the "hello world".
>> >> >
>> >> > my environment is:
>> >> > 1. uclinux.dist 2008
>> >> > 2. and I put my source code under user and compile it.
>> >> > 3. I use arm-linux-2006 to compile kernel
>> >> > 4. I use arm-linux-2007 to compile my hello world.
>> >> hi:
>> >> I have one question about my problem.
>> >> Can I replace the kernel execute command, "/init", as "/hello"; that
>> >> means the first user space program is hello, not standard int.
>> >> Is that the problem which make printt not workable?
>> >>
>> >> I have no idea whether kernel has to do something in "init" such that
>> >> "hello" can call printf to show message.
>> >
>> > [f]printf ultimately results in write() syscalls performed on
>> > open file descriptors.
>> >
>> > If you have trouble verifying that your userspace programs
>> > are able to execute, start with this test program:
>> >
>> > int main() {
>> > write(1, "Hello\n", 6);
>> > for (;;)
>> > continue;
>> > }
>> >
>> > Compile it and run as init. You should see "Hello"
>> > message. If you don't, your toolchain is producing broken
>> > executables.
>> > --
>> > vda
>> >
>>
>> Hi:
>> I have search the calls.S in arch/arm/kernel, but I cannot find the
>> sys call, write, you mention.
>> ( I use arm platform, so I search the syscalls implemented by arm)
>> Is it a wrap function? If so, I guess I should include some header to do
>> so.
>> But I have no idea what header I can use.
>
> Check which system call does uclibc call for printf(). It might help.
Hi:
I try to do that before.
in uclibc, _stdio.c, there are 3 _stdio_streams[] receiving the
printf messages.
Then I cannot find how uclibc calling which sys call to pass these streams.
thanks for your help,
miloody
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