Memory mapped files Are they still used.

Question

To System  programmers.
In some of my old code David used memory mapped files in handling huge sets of random points.  The code reads in the whole file and then sets flags similar to an async process.  The filemapping handles memory instead of using mallocs.  the
data maybe stored on the heap or in hte global stack.  I went back to Viusal Studio 6 and tried to take out the code as the standard c++ handles a full file read as a char buffer as a void * structure.  I found some valloc data types and
then found the newer filemapping routines in VS2013. Plus an explanation of global stack and heap.
Are software developers using file mapping or are they using say vectors to form stl structures.
Cheers
John Keays
John Keays

Answer 1

Here is some typical code in the old C.  This is close to the code I used in Visual studio 6.  I need to put this in vs2013 under c++ or C++ 11/14.  I have guessed the file handle open and size code.
main{
int fsize, numRecords;
Point *allPoints;
 fsize = readAllFile(name, &allPoints);
numRecords = fsize/ sizeof(Point);
for (i=0; i < numRecords:; I++)  printf("rec %d values x %.3f\n", i, allPoints[i].x);
int
readAllFile(char*name, void **addr){
file *fh;
int fsize;
openf(fh, name);
fsize = getfilesize(fh);
*addr = malloc(sizeof(char)*fsize);
fclose(fh);
return fsize;
This is the boilerplate for the file reads.  Even tried this with text files and parsing the text records.  Instead of the mallocs you suggest vector and the scheme of the code remains the same.
For a lidar file the xyz records have grown from 10,000 in the 1990's to 1,000,000 points in the mid 2000's.  For this size file 24 M bytes are allocated in one hit.  The whole of the Gold Coast in terms of lidar points in 2003 was 110 million
points.  It could be more.
Where is the data stored in the Malloc, Vector or memory Mapped file.  What is good and bad practice.
Cheers
john Keays
John Keays