i was trying to access the address of the character pointer it gives me the values stored in the variable.
Code: #include<iostream>
using namespace std;
int main()
{
char *i;
[Code]....
why is my code not giving the address of the variable i when it is a character pointer.
I want to assign an address location to a pointer and wanted to display the value at that memory location.I wrote a small program for this and it is like this : (i am using gcc 4.4 compiler)
# include "stdio.h"
int main()
{
unsigned int *a;
a=(unsigned int *)0x3f8;
printf("%u",*a);
return 0;
}
But it is giving Segmentation fault
How do I get the page pointer from a physical address?
View 1 Replies View RelatedWhen I try to access at physical address (0xD0000), we known that it is necessary to convert physical address to virtual address using function IOREMAP(0xD0000, 1024) and return me 0xC00D0000.
Now our doubt is when I have a board with I/O in address 0x150, is it necessary to convert this address to other virtual address??? or with inb(0x150) return me state of I/O in this address? How can I known where is this I/O address in my map memory?
I have been googling trying to fix this ... basicly I have a (int **) variable, and when I try to pass a (int) value to a specific position, I have seg.fault.Resuming what I have is:
int ** p;
p[0][0] = 1; //segmentation fault
I am receiving that error through Valgrind, I don't know the meaning of the error so I don't know what to check.
View 2 Replies View RelatedKernel 2.6.21.5, slackware 12.0
nasm 2.03.01
ld 2.17
GNU gdb 6.6
This GDB was configured as "i486-slackware-linux".
Code:
What could the cause of the message output by gdb possibly be? Reading some tutorials, I've learn the flat memory model is used in linux. So, in particular, I needn't care about the DS segment register.
Also, line 7 in the listing above, suggests nasm is assuming 32-bit addressing and so, I think it is using the flat memory model.
1.What character instructd the shell to interpret a special character as an ordinary character?
2.What directory contains some of the utilities available on the system in the form of binary files?
3. What command is used to search the location of a utility?
4. What command is used to instruct the editor to write the file and quit the editor?
5. What key quits the more utility and displays the shell prompt?
6. What command starts a child shell as the super user, taking on root's identity and environment?
7. Which wildcard characters can be used for searching all the files in the system that start with "A"?
8. The user name or login name of the super user is????
[Code]....
I want to pass ip address,port address and some parameters from command line using python script.The ip address and port address for establishing socket connection and remaining parameters to execute different connection.
View 1 Replies View Relatedif i attach a shared memory to my process whch part of the address space it will add(like stack, heap, data, code...).
View 3 Replies View RelatedI need a small shell based program that prints the mac address of physical ethernet adapter from it's firmware. I need this utility for license generation and appliance activation. I have tried several example but none of them is flawless, The easiest method I have found is to parse the output of "ifconfig" command but it has also some drawbacks.
1. Firstly program should differentiate between physical and virtual adapters. Physical means installed on board(wired or wireless) or installed additionally. Virtual adapters are those created by VPN or created by virtualization apps such as VirtualBox/VMWare etc. I am not interested in virtual ones.
2. In case of more them one physical adapters(wired and wireless), it should print the mac address and description(name & vendor) of both/all adapters.
3. If media is disconnected then also it should be able to read the mac address and description(name, vendor) of card.
4. This one is bit complex. I know that 'ethtool' can show you the universal mac address but it's limited to use only 2 types of drivers and won't work in all cases.
I want to translate the virtual address to physical address in linux C application, how to do that?
View 1 Replies View Relatedi have a xeon machine with ubuntu os machine specification is 3gb RAM 3 scsi hard drives each 73gb it have two ethernet cards one ethernet card is connected with adsl modem and the second is connected with LAN. now what is mikrotik doing for me is control access to bind mac adress with ip adress and control the band width for induvisual conection.
View 2 Replies View RelatedIs it possible to check if a pointer is deleted in C++ (using GDB)? For example:
Code:
a = new Thing();
b = a;
delete a;
// If all I have is the variable "b", how can I tell if it was deleted?
So far I have this:
Code:
int mm_init (mm_t *MM, int hm, int sz) {
int i;
[code]...
I'm trying to write a simple program that lists a menu and then asks you for your decision, and you can answer with a number or the name. However, I don't know how to add the second options (name).
View 14 Replies View Related#!/bin/bash
sed -n 8p file.txt
returns the 8th line to the StdOut.
If I assign the value to the variable line = $(sed -n 8p file.txt)
and now print it out with echo
echo $line
the line would be printed.
But what if the file has only 4 lines. What value would be assigned to the variable line?
I want to know that because I want to only print it if the value is "something", that is not null.
In Java for example I would do it like this...
String line = "";
line = reader.readLine(); // or anything else..
if(line!=null){
System.out.println(line);
}
How would I check if the value is not "null"(I don't know if bash knows null)
Code:
#include <stdio.h>
int main ()
[code]...
Whats the practical diffrens between these declarations in c?
char *a_str = "hello";
char a_str[] = "hello";
I'm getting some information about C language and this session of a C book (follow the above link) is using a bad example for me. When I'm trying this example of function returning a pointer, my compiler is stating a warning that I return a pointer to a local variable. I realized that it is error prone after all this variable may be override before the function has done his execution. And the author is fooling me saying that this example is "perfectly safe". I'm wrong? There is something that I don't got yet? Sorry but this site is preventing me to post the link of book cause I'm a newbie, so a need the hack it. Just strip out the question signs:
{LINK}
?w?w?w
?cs.cf.ac.uk?
[code]....
i am trying to find the size of an array, not by using the array as a parameter to "sizeof", but by using a pointer -pointing to the array- as a parameter. How do i do this?I use a 32-bit PC.Here's:
Code:
#include <string>
#include <iostream>
[code]...
This is one of the strangest problems I've run into while programming. Maybe there's just something wrong with my version of gcc or something.
The main problem comes at this point in the code:
Code:
po = makePoFromScorbotXYZPR(X, Y, Z, P, R);
h = makeHB2GFromPo(po);
printf("%le", *h[1][0]); //##################################### Here it has the right value
printf("%s", "
[Code].....
I have got following code from a book:
Code:
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <stdlib.h>
#define PORTNUMBER 12345
[Code]...
From "man gcc"
-Wno-int-to-pointer-cast (C and Objective-C only)
Suppress warnings from casts to pointer type of an integer of a different size.
[code]...
I have been trying to get a void pointer cast to work and I seem to have some problems. My code compiles, but when I execute it gives back garbage data. I'm not sure what I'm doing wrong.
Code:
int main()
{
[code]....
How could i create a script that will move the mouse pointer around the screen.i'm thinking i need the Xlib modules (which i have installed) but don't know how to implement them
View 5 Replies View RelatedI have a problem with correctly using a void pointer. I am writing a system that can open plugins and run them, and so far everything is going fine: I have a struct with some variables in, some function pointers, and I've written a small library to handle these correctly to communicate with the plugin. My challenge is that I need to put a pointer (let's call it "context") into this struct. The type is not important to the main body of code, and it is not ever used except by the plugin. The plugin will malloc some space for itself, and this *context will then point to whatever malloc returned. context is the address to a struct that I typedeffed to "ctxt".
Here is the first struct I mentioned:
Code:
typedef struct slave {
int val1;
int val2;
int (*entry)(struct slave*, int a, int b);
void *context;
} target;
Here are some snippets from the plugin:
Code:
typedef struct context {
int a;
int b;
} ctxt;
(*target).context = malloc(sizeof(struct ctxt));
So that (*target).*(ctxt)*context.a should refer to the int a in struct context.
But the error that the compiler gives me is a syntax one:
"expected identifier before '*' token"
Is my logic correct? Is my C correct?
I have a string like this "/home/test/filename.txt" and i want to delete all character after the last "/". how to do that using sed or awk.
View 5 Replies View RelatedI was reading Kernighan Ritchie book chapter 4 which deals with character pointers.I am not able to understand following different type of declarations
Code:
char aname[][15] = { "Illegal month", "Jan", "Feb", "Mar" };
char amessage[] = "now is the time";
[code]...
i am compiling the following program in linux. it's in c language. after the compilation with gcc when i run the executable file. it asks for input. but when i enter a name. i prints "Segmentation fault" and then terminate the program. can you please help me.
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <unistd.h>
[code]....