programmer questions - MMAP

[Wojciech Puchar]

>>
>> #include <sys/mman.h>
>> #include <fcntl.h>
>> #include <stdio.h>
>> #include <unistd.h>
>> main() {
>>  int ff=open("test",O_RDWR|O_CREAT,0666);
>>  char *adr;
>>  lseek(ff,1<<24,0);
>>  write(ff,"",1);
>>  adr=mmap(0,1<<24,PROT_READ|PROT_WRITE,MAP_NOCORE,ff,0);
>
> Try MAP_NOCORE|MAP_SHARED here. It's probably defaulting to a private
> mapping.

WORKS!!! thank you.

another question - do i need to create 16MB hole to be able to write 
directly up to 16MB data. it would be nice if mmap is able to extend the 
file as needed without lseek/write. is it possible?