Funcion: Fpmmap()
Sintaxis:

function Fpmmap(
 
  start: pointer;
 
  len: size_t;
 
  prot: cInt;
 
  flags: cInt;
 
  fd:

Descripcion: mapea o desmapea archivos o dispositivos en memoria. Los diferentes argumentos determinan que y como el archivo es mapeado:

adr
Address where to mmap the device. This address is a hint, and may not be followed.
len
Size (in bytes) of area to be mapped.
prot

Protection of mapped memory. This is a OR-ed combination of the following constants:

PROT_EXEC
The memory can be executed.
PROT_READ
The memory can be read.
PROT_WRITE
The memory can be written.
PROT_NONE
The memory can not be accessed.

flags

Contains some options for the mmap call. It is an OR-ed combination of the following constants:

MAP_FIXED
Do not map at another address than the given address. If the address cannot be used, MMap will fail.
MAP_SHARED
Share this map with other processes that map this object.
MAP_PRIVATE
Create a private map with copy-on-write semantics.
MAP_ANONYMOUS
fd does not have to be a file descriptor.

One of the options MAP_SHARED and MAP_PRIVATE must be present, but not both at the same time.
fd
File descriptor from which to map.
off
Offset to be used in file descriptor fd.

The function returns a pointer to the mapped memory, or a -1 in case of en error.

ERRORES:
Cuando un error suceda, la funcion retorna -1. mas informacoin se puede obtener con la funcion FpGetErrno

Sys_EBADF
fd is not a valid file descriptor and MAP_ANONYMOUS was not specified.
Sys_EACCES
MAP_PRIVATE was specified, but fd is not open for reading. Or MAP_SHARED was asked and PROT_WRITE is set, fd is not open for writing
Sys_EINVAL
One of the record fields Start, length or offset is invalid.
Sys_ETXTBUSY
MAP_DENYWRITE was set but the object specified by fd is open for writing.
Sys_EAGAIN
fd is locked, or too much memory is locked.
Sys_ENOMEM
Not enough memory for this operation.

Vea tambien
FpMUnMap
Ejemplo:

Program Example66;
 
{ Program to demonstrate the MMap function. }
 
Uses BaseUnix,Unix;
 
Var S    : String;
    fd   : cint;
    Len  : longint;
//    args : tmmapargs;
    P    : PChar;
 
begin
  s:='This is the string';
  Len:=Length(S);
  fd:=fpOpen('testfile.txt',O_wrOnly or o_creat);
  If fd=-1 then
    Halt(1);
  If fpWrite(fd,S[1],Len)=-1 then
    Halt(2);
  fpClose(fd);
  fd:=fpOpen('testfile.txt',O_rdOnly);
  if fd=-1 then
    Halt(3);
  P:=Pchar(fpmmap(nil,len+1 ,PROT_READ or PROT_WRITE,MAP_PRIVATE,fd,0));
 
  If longint(P)=-1 then
    Halt(4);
  Writeln('Read in memory  :',P);
  fpclose(fd);
  if fpMUnMap(P,Len)<>0 Then
    Halt(fpgeterrno);
end.