sbrk

NAME

       brk, sbrk - change data segment size

SYNOPSIS

       #include <unistd.h>

       int brk(void *end_data_segment);
       void *sbrk(ptrdiff_tincrement);

DESCRIPTION

       brk  sets  the end of the data segment to the value speci-
       fied by end_data_segment.  end_datasegment must be greater
       than  end  of  the text segment and it must be 16kB before
       the end of the stack.

       sbrk increments the  program's  data  space  by  increment
       bytes.   sbrk  isn't a system call, it is just a C library
       wrapper.

RETURN VALUE

       On success, brk returns zero, and sbrk returns  a  pointer
       to  the  start of the new area.  On error, -1 is returned,
       and errno is set to ENOMEM.

CONFORMING TO

       BSD 4.3

       brk and sbrk are not defined in the  C  Standard  and  are
       deliberately excluded from the POSIX.1 standard (see para-
       graphs B.1.1.1.3 and B.8.3.3).

SEE ALSO

       execve(2), getrlimit(2), malloc(3), end(3)