end(3) [netbsd man page]

END(3)							   BSD Library Functions Manual 						    END(3)

NAME

     end, etext, edata -- end boundaries of image segments

SYNOPSIS

     extern int end;
     extern int etext;
     extern int edata;

DESCRIPTION

     The globals end, etext and edata are program segment end addresses.

     etext is located at the first address after the end of the text segment.

     edata is located at the first address after the end of the initialized data segment.

     end is located at the first address after the end of the data segment (BSS) when the program is loaded.  Use the sbrk(2) system call with
     zero as its argument to find the current end of the data segment.

SEE ALSO

     sbrk(2), malloc(3), a.out(5)

HISTORY

     An end manual page appeared in Version 6 AT&T UNIX.

BUGS

     Traditionally, no variable existed that pointed to the start of the text segment because the text segment always started at address zero.
     Although it is no longer valid to make this assumption, no variable similar to the ones documented above exists to point to the start of the
     text segment.

BSD
								 September 1, 2005							       BSD

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 3.44 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)