How to print to console (Linux) without the standard library (libc) - c

Question

I'm not using the standard library, since my target x86 Linux distro is very limited.
#include <unistd.h>
void _start () {
const char msg[] = "Hello world";
write( STDOUT_FILENO, msg, sizeof( msg ) - 1 );
}
I want to print text to console, but I can't, is there any other way to do this.
The code above wont work because it depends on standard library
gcc Test.cpp -o Test -nostdlib

Answer 1

If you don't have libc, then you need to craft a write() system call from scratch to write to the standard output.
See this resource for the details: http://weeb.ddns.net/0/programming/c_without_standard_library_linux.txt
Code example from the above link:
void* syscall5(
void* number,
void* arg1,
void* arg2,
void* arg3,
void* arg4,
void* arg5
);
typedef unsigned long int uintptr; /* size_t */
typedef long int intptr; /* ssize_t */
static
intptr write(int fd, void const* data, uintptr nbytes)
{
return (intptr)
syscall5(
(void*)1, /* SYS_write */
(void*)(intptr)fd,
(void*)data,
(void*)nbytes,
0, /* ignored */
0 /* ignored */
);
}
int main(int argc, char* argv[])
{
write(1, "hello\n", 6);
return 0;
}