NAME
     wnmemd -- debugging aids for applications using wnmem

SYNOPSIS
     #include "wnlib.h"

     wn_gp_fill()

     wn_gp_pad()

     wn_stack_fill()

     wn_gp_trap_address(address)
     ptr address;

     wn_allmem_verify()

     wn_group_verify(group)
     wn_memgp group;

     int wn_mem_used()

     int wn_group_mem_used(group)
     wn_memgp group;

     wn_print_mem_used()

     wn_print_group_mem_used(group)
     wn_memgp group;

     wn_print_all_groups_mem_used()

     bool wn_mem_in_group(p,group)
     ptr p;
     wn_memgp group;

     wn_print_gp_stack()

     wn_gplabel(label)
     char label[];

DESCRIPTION
     These routines aid in debugging applications that use 
     wnmem.  In particular, these routines help detect the following
     problems:

          1)  use of uninitialized allocated memory

          2)  use of memory that has already been freed

          3)  array overflows and wild stores

          4)  leakage of memory.  Memory is lost but not freed.

     "wn_gp_fill" helps detect problems 1 and 2 above.  It should be
     called before any of the wnmem calls.  If "wn_gp_fill" has been called,
     "wn_alloc" fills memory it returns with 'a' characters, ensuring
     that this memory is not NULL.   Application code that is relying
     on this memory to be NULL will probably crash immediately and reliably.
     Further, "wn_gp_free" and "wn_free" fill memory they free
     with 'f' characters; application code that continues 
     to rely on this memory will probably crash immediately and reliably.

     "wn_gp_pad" helps detect problem 3 above.  It should be called
     before any of the wnmem calls.  If "wn_gp_pad" has been called,
     "wn_alloc" and "wn_zalloc" allocate an extra block of memory
     called a pad, in addition to the requested memory.  The
     pad memory is initialized to a known value.  Because the pad
     is contiguous with the requested memory, it will probably be
     overwritten in the event of an array overflow or a wild store.
     "wn_allmem_verify" checks if any of the pads are changed; if
     so it crashes with a message.  Use "wn_allmem_verify" to
     binary search the application for the problem.

     "wn_allmem_verify" checks the memory allocator for inconsistancies.
     If "wn_gp_pad" has been called, it helps detect array overflows and
     wild stores.  

     "wn_group_verify" verifies an individual memory group.

     "wn_print_mem_used" prints the total amount of memory allocated but
     not freed, which is helpful for detecting memory leaks.

     "wn_print_group_mem_used" prints the total amount of memory allocated
     but not freed in the memory group, which is helpful for
     detecting memory leaks.

     "wn_print_all_groups_mem_used" prints the total amount of memory
     allocated but not freed in each memory group separately, then
     prints a total for all groups.

     "wn_mem_in_group" returns TRUE iff pointer "p" was allocated
     from memory group "group".

     "wn_print_gp_stack" prints the memory group stack.

     "wn_gplabel" assigns a char string label to the current group
     for debugging purposes.  Other routines use this label if it
     is available.  Use "wn_gplabel" immediately after "wn_gpmake".

     "wn_gp_trap_address" causes allocations of memory at "address"
     to crash.  Useful for finding where a pointer is allocated.

BUGS

SEE ALSO
     wnmem, wnmlc, wnmems

     man/papers/heisen.bug

AUTHOR
     Will Naylor