On 12/03/2010 01:48 AM, Jiri Denemark wrote:
virDrvSupportsFeature API is allowed to return -1 on error while all but one uses of VIR_DRV_SUPPORTS_FEATURE only check for (non)zero return value. Let's make this macro return zero on error, which is what everyone expects anyway. --- src/driver.h | 8 ++++---- src/libvirt.c | 5 ++++- 2 files changed, 8 insertions(+), 5 deletions(-)
That is, if you care about the possibility of an error, call the function directly; and if you use the macro, then you don't care about errors and are happy treating an error the same as not present. Seems reasonable.
diff --git a/src/driver.h b/src/driver.h index b770e5e..e797a75 100644 --- a/src/driver.h +++ b/src/driver.h @@ -52,12 +52,12 @@ typedef enum { * Note that you must check for errors.
However, this comment is no longer applicable. So you'll need a v2 that fixes the documentation, and make it explicit that the macro ignores errors, as well as a cross-reference to the actual function for someone that cares about errors.
* * Returns: - * >= 1 Feature is supported. + * != 0 Feature is supported. * 0 Feature is not supported. - * -1 Error. */ -# define VIR_DRV_SUPPORTS_FEATURE(drv,conn,feature) \ - ((drv)->supports_feature ? (drv)->supports_feature((conn),(feature)) : 0) +# define VIR_DRV_SUPPORTS_FEATURE(drv,conn,feature) \ + ((drv)->supports_feature ? \ + (drv)->supports_feature((conn), (feature)) > 0 : 0)
-- Eric Blake eblake@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org