First, continue with your posted C. Using Newx (a malloc) will just leak the memory.
Second: put a debugging fprintf(stderr, "rados_pool_list()=%d\n", buf_sz); after the first rados_pool_list() call.

What does it print? A reasonable positive size? (I assume your C compiler is C99 capable; if not, you can rewrite the char buf[buf_sz]; as char *buf = alloca(buf_sz);).

Now, if rados_pool_list() returned a negative (error) value, try passing it "" in stead of NULL.
A quick glance at librados.cc makes me think there may be a bug there.

Oooomh, a quick update: another thing you should do is replace 

  int buf_sz;
with a 
  size_t buf_sz;
This, unfortunately will not improve the situation, since rados_pool_list() is prototyped as int, where it really ought to be ssize_t rados_pool_list(). File a ticket with the project?

In reply to Re: [Ceph::RADOS] Help Debugging Inline C by oiskuu
in thread [Ceph::RADOS] Help Debugging Inline C by three18ti

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