Re: [Valgrind-users] Uninitialized values with fortran

[John R. <jr...@bi...>]

>    # http://udrepper.livejournal.com/11429.html
>    export MALLOC_PERTURB_=$(($RANDOM % 255 + 1))
>    echo 1>&2 MALLOC_PERTURB_=$MALLOC_PERTURB_  " # $HOME/.bash_profile"
> This will cause all bytes in newly malloc()ed areas to be set to the
> same random byte.  [Or, specify a constant such as
>    export MALLOC_PERTURB_=0xF5

The current implementation within glibc-2.17 uses
    (0xff & (0xff ^ atoi(getenv("MALLOC_PERTURB_"))))
so you suffer the vagaries of atoi() and a bit-wise complement.