On Mon, Dec 17, 2012 at 02:25:05PM +0800, Wenchao Xia wrote: This patch has nothing to do with snapshots, so "snapshot: add error set function" is not a useful commit message. "error: add error_set_replace()" would be okay. Please use git log <filename> on the file you are modifying to find good component names (e.g. "block:", "error:").
> @@ -29,6 +29,9 @@ typedef struct Error Error; > */ > void error_set(Error **err, ErrorClass err_class, const char *fmt, ...) > GCC_FMT_ATTR(3, 4); > > +void error_set_replace(Error **err, ErrorClass err_class, const char *fmt, > ...) > +GCC_FMT_ATTR(3, 4); > + > /** > * Set an indirect pointer to an error given a ErrorClass value and a > * printf-style human message, followed by a strerror() string if > @@ -43,6 +46,12 @@ void error_set_errno(Error **err, int os_error, ErrorClass > err_class, const char > error_set(err, ERROR_CLASS_GENERIC_ERROR, fmt, ## __VA_ARGS__) > #define error_setg_errno(err, os_error, fmt, ...) \ > error_set_errno(err, os_error, ERROR_CLASS_GENERIC_ERROR, fmt, ## > __VA_ARGS__) > +#define error_setg_replace(err, fmt, ...) do { \ > + if (*err != NULL) { \ > + error_free(*err); \ > + } \ > + error_set(err, ERROR_CLASS_GENERIC_ERROR, fmt, ## __VA_ARGS__); \ > +} while (/*CONSTCOND*/0) Why not use error_set_replace() to get rid of the error_free() check? Stefan