c++ - mmap() vs. reading blocks

c++ - mmap() vs. reading blocks

I'm working on a program that will be processing files that could potentially be 100GB or more in size. The files contain sets of variable length records. I've got a first implementation up and runnin…


Is there a better way than parsing/proc/self/maps to figure out memory protection?

On Linux(or Solaris) is there a better way than hand parsing/proc/self/maps repeatedly to figure out whether or not you can read, write or execute whatever is stored at one or more addresses in mem…


c++ - appending to a memory-mapped file

I'm constantly appending to a file of stock quotes(ints, longs, doubles, etc.). I have this file mapped into memory with mmap. What's the most efficient way to make newly appended data available as…


mmap, msync and linux process termination

I want to use mmap to implement persistence of certain portions of program state in a C program running under Linux by associating a fixed-size struct with a well known file name using mmap() with the…


Python mmap 'Permission denied' on Linux

I have a really large file I'm trying to open with mmap and its giving me permission denied. I've tried different flags and modes to the os.open but its just not working for me. What am I doing wrong…


c - Mmap() an entire large file

I am trying to "mmap" a binary file(~ 8Gb) using the following code(test.c).#include<stdio.h>#include<stdlib.h>#include<stdint.h>#include<sys/mman.h>#include<sys/types.h>#include<sys/sta…



how can I detect whether a specific page is mapped in memory?

I would like to detect whether or not a specific page has already been mapped in memory. The goal here is to be able to perform this check before calling mmap with a fixed memory address. The followin…


What is the difference between MAP_SHARED and MAP_PRIVATE in the mmap function?

Playing around with mmap for the fun of it, I have the following code:(.. snip..) fd=open("/home/me/straight_a.txt", O_RDONLY); if(fd==-1){perror("open"); exit(1);}m=mmap(NULL, 4…


linux - What’s the purpose of mmap memory protection PROT_NONE

I was reading the documentation of mmap and fell upon this line: PROT_NONE Pages may not be accessed. Is there any use to map a file to memory but never access it?…


Do I need to keep a file open after calling mmap on it?

I have a program that maps quite a few(100's) of sizable files 10-100MB each. I need them all mapped at the same time. At the moment I am calling open followed by mmap at the beginning of the program…




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