PR_SET_MM_START_BRK(2const)                        PR_SET_MM_START_BRK(2const)

NAME
       PR_SET_MM_START_BRK - modify kernel memory map descriptor fields

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <linux/prctl.h>  /* Definition of PR_* constants */
       #include <sys/prctl.h>

       int prctl(PR_SET_MM, PR_SET_MM_START_BRK, unsigned long addr, 0L, 0L);

DESCRIPTION
       Set the address above which the program heap can be expanded with
       brk(2) call.

       The address must be greater than the ending address of the current
       program data segment.  In addition, the combined size of the resulting
       heap and the data segment can't exceed the RLIMIT_DATA resource limit
       (see setrlimit(2)).

RETURN VALUE
       On success, 0 is returned.  On error, -1 is returned, and errno is set
       to indicate the error.

ERRORS
       EINVAL addr is greater than TASK_SIZE (the limit on the size of the
              user address space for this architecture).

       EINVAL addr is less than or equal to the end of the data segment or
              specifies a value that would cause the RLIMIT_DATA resource
              limit to be exceeded.

STANDARDS
       Linux.

HISTORY
       Linux 3.3.

SEE ALSO
       prctl(2), PR_SET_MM(2const)

Linux man-pages 6.19              2026-02-08       PR_SET_MM_START_BRK(2const)