Re: [Libguestfs] [PATCH v2 1/2] appliance: search all types of appliances for each path separately

On 05/05/2017 12:18 PM, Eric Blake wrote: > On 05/05/2017 12:07 PM, Richard W.M. Jones wrote: >> Eric, what do you think of Pavel's analysis and/or suggested fix >> below? It seems all too plausible to me unfortunately :-( >> >>> There NULL is macros which can be defined as 0 or (void*)0, again in >>> accordance with c99: > C99 permits: > #define NULL 0 > > but POSIX does not. POSIX _requires_ > > #define NULL ((void*)0) > > or the equivalent, so that NULL is properly typed as a pointer to void > in ALL cases (rather than the weaker C99 solution of letting the integer > zero constant leak), in part _because_ of the commonality of passing > NULL through varargs functions. I forgot to cite my reference: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stddef.h.html#ta... "NULL Null pointer constant. [CX] [Option Start] The macro shall expand to an integer constant expression with the value 0 cast to type void *. [Option End]" ... "RATIONALE The ISO C standard does not require the NULL macro to include the cast to type void * and specifies that the NULL macro be implementation-defined. POSIX.1-2008 requires the cast and therefore need not be implementation-defined." where the CX option represents requirements that POSIX makes above-and-beyond bare C99.