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brk(2) - brk, sbrk, brk, sbrk - change data segment size - man 2 brk

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BRK(2)                     Linux Programmer's Manual                    BRK(2)



NAME
       brk, sbrk - change data segment size

SYNOPSIS
       #include <unistd.h>

       int brk(void *end_data_segment);

       void *sbrk(intptr_t increment);

DESCRIPTION
       brk  sets  the  end  of  the  data  segment  to  the value specified by
       end_data_segment, when that value is reasonable, the system  does  have
       enough  memory  and  the process does not exceed its max data size (see
       setrlimit(2)).

       sbrk increments the program's data  space  by  increment  bytes.   sbrk
       isn't a system call, it is just a C library wrapper.  Calling sbrk with
       an increment of 0 can be used to find the current location of the  pro-
       gram break.

RETURN VALUE
       On  success,  brk returns zero, and sbrk returns a pointer to the start
       of the new area.  On error(8,n), -1 is returned, and errno is set(7,n,1 builtins) to ENOMEM.

CONFORMING TO
       BSD 4.3

       brk  and  sbrk  are  not defined in(1,8) the C Standard and are deliberately
       excluded from  the  POSIX.1  standard  (see  paragraphs  B.1.1.1.3  and
       B.8.3.3).

NOTES
       Various  systems use various types for the parameter of sbrk().  Common
       are int, ssize_t, ptrdiff_t, intptr_t.  XPGv6 obsoletes this  function.

SEE ALSO
       execve(2), getrlimit(2), malloc(3)



Linux 2.4                         2003-11-01                            BRK(2)

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