mmap - MAP_ANON ??

[Lance Heller <lheller@wcom.com>]

Hello all,

   While the 'mmap(2)' manpage of my x86 2.2r2 (2.2.18 kernel) 
system says "Linux also knows about MAP_DENYWRITE,  MAP_EXECUTABLE 
and MAP_ANON(YMOUS)", I've not been able to get 'MAP_ANON' to work.  
For example the mmap call below returns an EINVAL:

#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <sys/mman.h>
      
extern int errno;
      
int
main(int argc, char** argv)
{
      
void* shared = NULL;

shared = mmap( NULL, getpagesize(), PROT_WRITE|PROT_READ, 
               MAP_SHARED|MAP_ANON, -1, 0 );

if( (int )shared == -1 )perror("bad mmap");
   
exit(0);
}

This builds cleanly using gcc version 2.95.2 and libc6 
version 2.1.3-18.  ( gcc -Wall -g junk.c )

Any help, pointers or suggestions will be gratefully accepted.


Lance


----------------------------------------------------------------------
Lance Heller                     |         
  Network Systems                |  WorldCom         
  email: lance.heller@wcom.com   |  6929 North Lakewood Avenue
  phone: (918)590-4921           |  Tulsa, OK  74117  
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