On Wed, 8 Mar 2017, sayli karnik wrote: > > > On Wed, Mar 8, 2017 at 12:47 AM, Greg Kroah-Hartman > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Wed, Mar 08, 2017 at 12:41:12AM +0530, sayli karnik wrote: > >> The patch groups similar macros into enum data types. > > > > Why? > > > > What benefit does this provide? > As suggested by Lars, I converted the macros to an enum data type, so that > it is clear what their function is- > https://groups.google.com/d/msg/outreachy-kernel/VM6Wu-fJVfQ/VngpohNBAwAJ > > > > >> > >> Signed-off-by: sayli karnik <karniksayli1995@xxxxxxxxx> > >> --- > >> Changes in v2: > >> Corrected the order of both the enums. > >> Used enum data type names instead of unsigned int inside struct > >> ad7280_platform_data. > >> > >> drivers/staging/iio/adc/ad7280a.h | 24 ++++++++++++++---------- > >> 1 file changed, 14 insertions(+), 10 deletions(-) > >> > >> diff --git a/drivers/staging/iio/adc/ad7280a.h > b/drivers/staging/iio/adc/ad7280a.h > >> index ccfb90d..e22694f 100644 > >> --- a/drivers/staging/iio/adc/ad7280a.h > >> +++ b/drivers/staging/iio/adc/ad7280a.h > >> @@ -13,15 +13,19 @@ > >> * TODO: struct ad7280_platform_data needs to go into include/linux/iio > >> */ > >> > >> -#define AD7280A_ACQ_TIME_400ns 0 > >> -#define AD7280A_ACQ_TIME_800ns 1 > >> -#define AD7280A_ACQ_TIME_1200ns 2 > >> -#define AD7280A_ACQ_TIME_1600ns 3 > >> +enum ad7280a_acq_time { > >> + AD7280A_ACQ_TIME_400ns = 0, > >> + AD7280A_ACQ_TIME_800ns, > >> + AD7280A_ACQ_TIME_1200ns, > >> + AD7280A_ACQ_TIME_1600ns, > > > > Before your change, you instantly knew that the 1600ns value needed to > > be 3. Now I need to count an enum. Does this seem like a better > > change? > > Hmm we do need to count. > But, > -I feel grouping into an enum organizes similar #defines in a better way. > > -You get free compile time checking of valid values using enums. For example > > public static int VALUE_ONE = 0; > public static int VALUE_TWO = 1; > > does not ensure, > > void selectOption(int value) { > ... > } > will only accept 0 or 1 as a parameter value. Using an enum, that is > guaranteed. Regrettably in C it is not. Still, using enums does make it possible to design tools that do such checking. With a random bunch of defines it is less clear what goes with what. > > -Also it avoids the repetitive #defines. > > >Are you _sure_ the compiler sets the values properly? Page 105 of this document WG14/N1256 Committee Draft — Septermber 7, 2007 ISO/IEC 9899:TC3 http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf says: An enumerator with = defines its enumeration constant as the value of the constant expression. If the first enumerator has no =, the value of its enumeration constant is 0. Each subsequent enumerator with no = defines its enumeration constant as the value of the constant expression obtained by adding 1 to the value of the previous enumeration constant. One could also check whether the actual value is important, eg the constant is passed to a device, or if it is just used as an internal flag. julia > > > > thanks, > > > > greg k-h > > -- > You received this message because you are subscribed to the Google Groups > "outreachy-kernel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to outreachy-kernel+unsubscribe@xxxxxxxxxxxxxxxx. > To post to this group, send email to outreachy-kernel@xxxxxxxxxxxxxxxx. > To view this discussion on the web visithttps://groups.google.com/d/msgid/outreachy-kernel/CAKG5xWiuKm2VboRAR2ALz%2 > BSnHPbcBTQvH2Hw%2BRpkfm2P%2BGK2Qg%40mail.gmail.com. > For more options, visit https://groups.google.com/d/optout. > >
