Do I need to close\free fopencookie?

TylerDense 0
Viewed 47

I create a pipe using fopencookie to open file by FILE handle inside gz, how would I need to cleanup? Do I need to close something but resulting handle?

For example there's a bz inside gz:

int do_close(void* f){
    return ::gzclose( reinterpret_cast<gzFile>(f)) ;
}

void main()
{
    cookie_io_functions_t func = {
        NULL,
        NULL,
        NULL,
        do_close
    };

    gzFile gzf = ::gzopen("test.gz", "r");

    FILE* fp = fopencookie(gzf , "r", func);

    BZFILE *bzf = BZ2_bzopen(fp , "r");

    BZ2_bzclose(bzf); 
//Do I need to close something but this?
//If this is not the end of program but is the end of file usage?
}
pipe linux c++
1 Answers

I don't see it explicitly specified in the documentation, but it seems clear that, given it returns a FILE *, it's expected that you call plain fclose for cleanup, which in turn will call your do_close.

OTOH from what I see in the sources BZ2_bzclose does close automatically the underlying FILE * associated with the BZFILE * calling fclose, so no extra fclose seems to be needed for your code...

... but looking at bzlib.h, I see that BZ2_bzopen is supposed to take a const char *, not a FILE *, so it doesn't seem correct at all. Probably you want to call BZ2_bzReadOpen instead? In that case, though, the cleanup function you are expected to call (BZ2_bzReadClose) doesn't call fclose, and you are supposed to do that on your own.

Matteo Italia0
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