understanding apr_strtok()

[Sam Carleton]

I am trying to use apr_strtok() for the first time.  I am taking the
add_cookie() function from mod_rewrite.c, no changes.  I am passing in
the string, variable 's':

KioskViewingStation:KVS_VERSION::5

The first line that executes in the function is:

    char *tok_cntx;
    var = apr_strtok(s, ":", &tok_cntx);

I am getting an access violation.  I have tried initializing tok_cntx
to NULL, but that does not seem to have any impact.  What is the
correct way to use apr_strtok()?

Sam