Solved

Segmentation fault on char array bit wise operation

Posted on 2006-10-22
2
293 Views
Last Modified: 2010-04-15
myFile.txt is a binary file:

Followed is the result of od -Ax -tx1 myFile.txt:
000000 68 01 00 00 a0 05 00 00 48 00 00 00 38 05 00 00

Followed is the complete code

#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>//O_RDONLY


int main(int argc, char *argv[])
{
     if (argc!=3){
          printf("Please enter exactly three arguments.\n");
     }else{
                 //myFile.txt is being memory map
          int f=open(myFile.txt,O_RDONLY);
          int n=lseek(f,0,SEEK_END);
          char * mf=mmap(0,n,PROT_READ,MAP_PRIVATE,f,0);
          int i;
          for (i=0;i<16;i++){
               mf[i]&=0x0F; //<--this gives me segmentation fault, what is the reason and how to correct it?
          }
         
     }

   return 0;
}



0
Comment
Question by:william007
2 Comments
 
LVL 45

Accepted Solution

by:
sunnycoder earned 500 total points
ID: 17783433
>mf[i]&=0x0F;
Assigns it back to mf[i] which has been mmaped using PROT_READ
0
 
LVL 9

Author Comment

by:william007
ID: 17794375
Thanks=)
0

Featured Post

Master Your Team's Linux and Cloud Stack!

The average business loses $13.5M per year to ineffective training (per 1,000 employees). Keep ahead of the competition and combine in-person quality with online cost and flexibility by training with Linux Academy.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Convert image to byte array 8 209
Problem to ASCII 1 195
How to translate this 2-line while loop into C from Perl? 8 119
Why  my code (program) build with old compiler? 11 76
Preface I don't like visual development tools that are supposed to write a program for me. Even if it is Xcode and I can use Interface Builder. Yes, it is a perfect tool and has helped me a lot, mainly, in the beginning, when my programs were small…
Examines three attack vectors, specifically, the different types of malware used in malicious attacks, web application attacks, and finally, network based attacks.  Concludes by examining the means of securing and protecting critical systems and inf…
The goal of this video is to provide viewers with basic examples to understand and use pointers in the C programming language.
Video by: Grant
The goal of this video is to provide viewers with basic examples to understand and use nested-loops in the C programming language.

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question