This is the most "minimal" legal C program. It is not obvious but main is in fact a function, not the real beginning of the compiled code. When you link a C program the linker adds (something like) two functions: _start() and _end() The actual names are implementation dependent. _start() sets up a lot of memory objects and files like stdout and stdin _end() cleans up after _start()
If main is not fully declared you get undefined behavior. Undefined behavior is just that - the program may dump core, panic the kernel, format your disk, or send family pictures to the Mars explorer.
This User Gave Thanks to jim mcnamara For This Post:
i just finished a project for a c++ class that i wrote at home on my computer, compiled with gcc. when i brought the code into school it would not compile, it would complain that cannot call main() function. at school we use ancient borland c++ from 1995. anyway my program has 20 different... (3 Replies)
Hi,
I have a main loop which calls a sub loop, which finally returns to the main loop itself. The main loop runs when a flag is set. Now, I have a signal handler for SIGINT, which resets the flag and thus stops the main loop. Suppose I send SIGINT while the program is in subloop, I get an error... (1 Reply)
Hi! I've a C program as shown below..
The line numbers and the statements of the program are separated by a space..
1 #include<stdio.h>
2 char a,b,c;
3 float x,y,z;
4 int main()
5 {
6 int d,e,f;
7 // further declarations
8 // further declarations
9 /* body*/
10 }
11 void fun1()
12... (1 Reply)
why does this not work?
#include <stdio.h>
#include <stdlib.h>
char getFileMode(char charChanger) {
char filetype; /*var to hold the value to be returned*/
filetype = charSetter; /*set filetype to "l" if it is a symlink*/
return filetype;
}
int main(void){
char... (8 Replies)
Hi friends,
when I am passing arguments to main, I want another function to be able to have access to that function, the problem is that I am creating athread, which has a function like void *xyz(void *), how can pass the refernce of argv to this function, if you see my program, you will better... (2 Replies)
H friends,
As we know, a function returns a value and that value is saved somwhere. like
int Sum( int x, int y )
{
return x + y;
}
Total = Sum( 10, 20 );
The value 30 is saved in variable Total.
Now the question is, what int value does the function main return, and where is it... (5 Replies)
Hello All,
I am trying to call a function from the calling main program from a dlopened library function, below is the entire code, when I execute it it crashes with sigill. Can you guys help me out I guess I am missing out on the linker flag or something here. besides I am new to AIX and... (1 Reply)
I feel that i am missing something obvious but i can't find what is wrong.
I have a script that is launching some functions with "&" and each call is feeding the array with a value. When all calls are finished I just want to retrieve the values of that array.
It is looking like that :
... (5 Replies)
Hi. I have some code, that for some reason, I could not post it here in this post. Here's the address for it:
#if 0 shc Version 4.0.1, Generic Shell Script Compiler GNU GPL Version 3 Md - Pastebin.com
First off, I used "shc" to convert the code from shell script to C.
And The... (6 Replies)
Discussion started by: ignatius
6 Replies
LEARN ABOUT OPENSOLARIS
_etext
end(3C) Standard C Library Functions end(3C)NAME
end, _end, etext, _etext, edata, _edata - last locations in program
SYNOPSIS
extern int _etext;
extern int _edata;
extern int _end;
DESCRIPTION
These names refer neither to routines nor to locations with interesting contents; only their addresses are meaningful.
_etext The address of _etext is the first location after the last read-only loadable segment.
_edata The address of _edata is the first location after the last read-write loadable segement.
_end If the address of _edata is greater than the address of _etext, the address of _end is same as the address of _edata.
If the address of _etext is greater than the address of _edata, the address of _end is set to the page boundary after the address
pointed to by _etext.
USAGE
When execution begins, the program break (the first location beyond the data) coincides with _end, but the program break can be reset by
the brk(2), malloc(3C), and the standard input/output library (see stdio(3C)), functions by the profile (-p) option of cc(1B), and so on.
Thus, the current value of the program break should be determined by sbrk ((char *)0).
References to end, etext, and edata, without a preceding underscore will be aliased to the associated symbol that begins with the under-
score.
SEE ALSO cc(1B), brk(2), malloc(3C), stdio(3C)SunOS 5.11 31 Mar 2006 end(3C)