You need to remember that pointers and arrays are not the same, no matter what anybody tells you. (There are some conveniences provided where you can treat an array as a pointer (and vice versa), but they hide what's really going on.) Your declaration as a pointer with "extern int *arr" makes the sizeof(void*) bytes at location "arr" get treated as if they point to something, when in fact they contain garbage since you've defined an array there, not a pointer. The first few bytes of the array (i.e. the garbage) are dereferenced as if they were a pointer, and a segfault is the likely result.
Solution: Make both the declaration and the definition the same. Additionally, put the declaration in a header and make sure that File1.c #includes it, and that will prevent this sort of thing from happening.
Last edited by JohnGraham; 07-21-2010 at 09:19 AM..
sometimes for this code i get a segmentation fault for codes llike this
:
int main{
int * a= 0;
int b;
a = (int*)malloc(sizeof(int));
///some code using these variable but no freeing of a
if(a){
free(a);
a = 0;
}
return... (3 Replies)
hello all,
I tried a program on an array to intialise array elements from the standard input device.it is an integer array of 5 elements.but after entering the 4th element it throws a message called "Segmentation Fault" and returns to the command prompt without asking for the 5th element.
... (3 Replies)
Hi ,
During execution a backup binary i get following error
"Program error 11 (Segmentation fault), saving core file in '/usr/datatools"
Riyaz (2 Replies)
Hi,
on a linux Red HAT(with Oracle DB 9.2.0.7) I have following error :
RMAN> delete obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 2
using channel ORA_DISK_1
Segmentation fault
What does it mean ? And the solution ?
Many thanks. (0 Replies)
Hi,
I am having this segmentation fault not in the following program, bt. in my lab program . My lab program is horrible long so cannot post it here bt. I am using the following logic in my program which is giving the segmentation fault. Bt. if I run this sample program as it is it dosen't give... (3 Replies)
i have this code
int already_there(char *client_names, char *username) {
int i;
for(i = 0; i<NUM; i++) {
printf("HERE\n");
if (strcmp(client_names, username)==0) return(1);
}
return(0);
}
and i get a segmentation fault, whats wrong here? (7 Replies)
I use a binary name (ie polo) it gets some parameter , so for debugging normally i do this :
i wrote script for watchdog my app (polo) and check every second if it's not running then start it , the problem is , if my app , remain in state of segmentation fault for a while (ie 15 ... (6 Replies)
Hi Guys,
I just installed and booted a zone called testzone. When I logged in remotely and tried changing to root user I get this error:
"Segmentation fault"
Can someone please help me resolve this?
Thanks alot (2 Replies)
I keep getting this fault on a lot of the codes I write, I'm not exactly sure why so I'd really appreciate it if someone could explain the idea to me.
For example this code
#include <stdio.h>
main()
{
unsigned long a=0;
unsigned long b=0;
int z;
{
printf("Enter two... (2 Replies)
Oddities with gcc, 2.95.3 for the AMIGA and 4.2.1 for MY current OSX 10.14.1...
I am creating a basic calculator for the AMIGA ADE *NIX emulator in C as it does not have one.
Below are two very condensed snippets of which I have added the results inside the each code section.
IMPORTANT!... (11 Replies)
Discussion started by: wisecracker
11 Replies
LEARN ABOUT LINUX
etext
END(3) Linux Programmer's Manual END(3)NAME
etext, edata, end - end of program segments
SYNOPSIS
extern etext;
extern edata;
extern end;
DESCRIPTION
The addresses of these symbols indicate the end of various program segments:
etext This is the first address past the end of the text segment (the program code).
edata This is the first address past the end of the initialized data segment.
end This is the first address past the end of the uninitialized data segment (also known as the BSS segment).
CONFORMING TO
Although these symbols have long been provided on most Unix systems, they are not standardized; use with caution.
NOTES
The program must explicitly declare these symbols; they are not defined in any header file.
On some systems the names of these symbols are preceded by underscores, thus: _etext, _edata, and _end. These symbols are also defined for
programs compiled on Linux.
At the start of program execution, the program break will be somewhere near &end (perhaps at the start of the following page). However,
the break will change as memory is allocated via brk(2) or malloc(3). Use sbrk(2) with an argument of zero to find the current value of
the program break.
EXAMPLE
When run, the program below produces output such as the following:
$ ./a.out
First address past:
program text (etext) 0x8048568
initialized data (edata) 0x804a01c
uninitialized data (end) 0x804a024
Program source
#include <stdio.h>
#include <stdlib.h>
extern char etext, edata, end; /* The symbols must have some type,
or "gcc -Wall" complains */
int
main(int argc, char *argv[])
{
printf("First address past:
");
printf(" program text (etext) %10p
", &etext);
printf(" initialized data (edata) %10p
", &edata);
printf(" uninitialized data (end) %10p
", &end);
exit(EXIT_SUCCESS);
}
SEE ALSO objdump(1), readelf(1), sbrk(2), elf(5)COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2008-07-17 END(3)