BRK(2)								System Calls Manual							    BRK(2)

NAME

       brk, sbrk - change memory allocation

SYNOPSIS

       #include <u.h>
       #include <libc.h>

       int   brk(void *addr)

       void* sbrk(ulong incr)

DESCRIPTION

       Brk sets the system's idea of the lowest bss location not used by the program (called the break) to addr rounded up to the next multiple of
       8 bytes.  Locations not less than addr and below the stack pointer may cause a memory violation if accessed.

       In the alternate function sbrk, incr more bytes are added to the program's data space and a pointer  to	the  start  of	the  new  area	is
       returned.  Rounding occurs as with brk.

       When  a program begins execution via exec the break is set at the highest location defined by the program and data storage areas.  Ordinar-
       ily, therefore, only programs with growing data areas need to use brk.  A call to sbrk with a zero argument returns the lowest  address	in
       the dynamic segment.

SOURCE

       /sys/src/libc/9sys/sbrk.c

SEE ALSO

       intro(2), malloc(2), segattach(2), segbrk(2)

DIAGNOSTICS

       These functions set errstr.

       The error return from sbrk is (void*)-1.

																	    BRK(2)