! 
! Random.c:  A program to be called from VAXTPU
! via call_user.  It will return a random number.

#include descrip
#include math

char random_string [1000];

tpu$calluser (code, instring, outstring)
int *code;
struct dsc$descriptor *instring, *outstring;
{
    int len;

    if (*code != 0) srand (*code);

    sprintf (random_string, "%d", rand());

    len = strlen (random_string);
    return lib$scopy_r_dx (&len, 
                           random_string,
                           outstring);
}

-----

!
! The options file to govern linking of random.exe
!

random.obj
psect_attr=random_string,noshr
universal=tpu$calluser

-----
!
! TPU command file to demonstrate call_user
!
message (call_user (1, ""));
message (call_user (0, ""));
message (call_user (0, ""));
message (call_user (0, ""));
message (call_user (0, ""));
message ("");
message (call_user (1, ""));

-----
!
! The DCL command file showing how to
! link random and how to make it possible
! for TPU to use it
!
$cc random
$
$define/user lnk$library sys$share:vaxcrtl
$link random/share/opt/map
$
$define/user tpu$calluser reinig$dua0:[reinig.tpu.calluser]random
$edit/tpu/nodis/nosec/command=random.tpu

------
!
! Sample output from the above command file
!
REINIG$ @random
%TPU-S-FILEIN, 7 lines read from file REINIG$DUA0:[REINIG.TPU]RANDOM.TPU;3
1103527590
377401575
662824084
1147902781
2035015474

1103527590