end.3

操作系统设计与实现源码

.\"	@(#)end.3	6.2 (Berkeley) 5/12/86
.\"
.TH END 3  "May 12, 1986"
.AT 3
.SH NAME
end, etext, edata \- last locations in program
.SH SYNOPSIS
.nf
.ft B
extern int etext;
extern int edata;
extern int end, _end;
.ft R
.fi
.SH DESCRIPTION
These names refer neither to routines nor to locations with interesting
contents.  The address of
.B etext
is the first address above the program text,
.B edata
above the initialized data region, and
.B end
above the uninitialized data region.
.B _end
is the same as
.BR end ,
but in the implementers name space, i.e. for use in libraries.
.PP
When execution begins, the program break coincides with
.BR end ,
but it is reset by the routines
.BR brk (2),
.BR malloc (3), 
standard input/output
.RB ( stdio (3)),
etc.
The current value of the program break is reliably returned by `sbrk(0)',
see
.BR brk (2).
.SH "SEE ALSO"
.BR brk (2),
.BR malloc (3).