Steve Hay <[EMAIL PROTECTED]> writes:
>Is it safe to store a pointer to a C struct in an SV?
Yes, provided the lifetime of the data pointed to is suitable.
>
> MY_STRUCT my_struct;
> sv = newSVuv((unsigned long) &my_struct);
> SvIOK_only_UV(sv);
Your my_struct is on the stack in the XS function - memory gets
reused when XS returns.
What I tend to do is put the struct in the string part of a SvPV
SV *sv = newSV(sizeof(MY_STRUCT));
MY_STRUCT *my_struct = (MY_STRUCT *) SvPVX(sv);
>
>and later on my_filter() can then access:
>
> (MY_STRUCT *) SvUVX(sv)
That would in my scheme be
MY_STRUCT *my_struct = (MY_STRUCT *) SvPVX(sv);
>
>However, the struct now available within my_filter() doesn't seem to be
>working properly...
>
>If I switch to using a file scope static variable for the struct then it
>works OK for one filtered source file, but this approach is not feasible
>in general because if one filtered source file loads another one then
>the second filter starts writing all over the struct that was being used
>by the first filter! They need to have their "own" structs available,
>hence I wanted to store a pointer to it on the SV.
>
>Is that a "safe" thing to do in general? Any ideas what might be going
>wrong here?
>
>Thanks,
>- Steve
>
>
>
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