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Re: [igraph] How to test for initialisation?
From: |
Tamás Nepusz |
Subject: |
Re: [igraph] How to test for initialisation? |
Date: |
Tue, 21 Jan 2014 17:40:55 +0100 |
> How can I test whether an igraph_t variable has been initialised already?
This is a bit of a hack, but in the worst case you can try the following.
Whenever you create an igraph_t on the stack or allocate an igraph_t on the
heap, set all of its bytes to zero using memset(). When you initialize a graph
using igraph_init, it is pretty sure that at least one of the bytes will be
changed in the igraph_t structure, so in the worst case you can create a
utility function that evaluates every single byte of an igraph_t and returns
true if and only if all the bytes are zeros. (However, you should also make
sure to call memset() again after an igraph_destroy() operation).
Now that I read it again, it seems even more horrible than before. Gabor’s
solution is definitely much better, but if you don’t feel like introducing a
myigraph_t for this purpose, this could be an alternative.
T.