I get an uninitialized memory warning in:
samba-3.0.23c/source/libsmb/libsmbclient.c
when reading from smb:///.

The problem is this code:
		strncpy(server, context->workgroup, 
			((strlen(context->workgroup) < 16)
                         ? strlen(context->workgroup)
                         : 16));
                server[server_len - 1] = '\0';

Limiting the strncpy to strlen(source) means the terminating zero won't be copied.