LD_PRELOAD Not Working with Custom getpid Function

#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>

pid_t getpid(void)
{
    printf("Initializing..\n");
    return syscall(SYS_getpid);
}

#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
int main()
{
    printf( "pid = %d!\n", getpid() );

    return 0;
}

LD_PRELOAD=./getpid.so ./testpid

ERROR: ld.so: object 'getpid.so' from LD_PRELOAD cannot be preloaded: ignored