Brann Douglas B Capt AFRL/DEBE <[EMAIL PROTECTED]> writes:
>Hi, I have what seemed like an easy problem a few hours ago, but I've been
>tring to figure out if an element of a hash table is defined or not.
>
>Essentially, I have a hash of arrays, and if the hash element is defined, I
>want to insert the element into it, but if the element isn't defined, I need
>to create it and add to it.
>
>Can somebody post a code snippet?
C<exists> and C<defined> are roughly as follows:
SV **svp = hv_fetch(...);
if (svp) {
/* exists */
if (SvOK(*svp)) {
/* defined */
}
if (SvROK(*svp) && SvTYPE(SvRV(*svp)) == SVt_PVAV) {
/* ref to array */
}
}
But you can do part of what you want by passing a true value to final "lval"
parameter of hv_fetch() and similar:
Perl_hv_fetch(pTHX_ HV *hv, const char *key, I32 klen_i32, I32 lval)
If lval is true, then hv.c will create an SV for you and 'svp' in code
fragment above will never be NULL.
