On 4/30/15, 11:22 AM, "Richardson, Bruce" <bruce.richardson at intel.com> wrote:
>On Thu, Apr 30, 2015 at 02:31:13PM +0000, Wiles, Keith wrote: >> >> >> On 4/30/15, 8:38 AM, "Olivier MATZ" <olivier.matz at 6wind.com> wrote: >> >> >Hi Keith, >> > >> >On 04/30/2015 03:24 PM, Wiles, Keith wrote: >> >> >> >> >> >> On 4/30/15, 4:45 AM, "Olivier MATZ" <olivier.matz at 6wind.com> wrote: >> >> >> >>> Hi Keith, >> >>> >> >>> Thank you for submitting a clean-up. Please see some comments below. >> >>> >> >>> On 04/29/2015 05:25 PM, Keith Wiles wrote: >> >>>> Trying to simplify the ifdefs in rte.app.mk to make the code >> >>>> more readable and maintainable by moving LDLIBS variable to use >> >>>> the same style as LDLIBS-y being used in the rest of the code. >> >>>> >> >>>> Added a new variable called EXTRA_LDLIBS to be used by example apps >> >>>> instead of using LDLIBS directly. >> >>> >> >>> If I understand well, the goal of this patch is only a cleanup in >> >>> rte.app.mk, but at the end, it changes the makefile user "API", >> >>> which could probably be a problem for applications using the >> >>> dpdk makefile framework. >> >>> >> >>> Why not just having an temporary internal variable (let's say >> >>> _LDLIBS-y) that would allow to do the clean-up without modifying >> >>> the user interface? >> >>> >> >>> Also, with your patch, the approach for EXTRA_LDLIBS would be >> >>> different than CFLAGS or LDFLAGS: >> >>> - CFLAGS/LDFLAGS are in Makefiles only >> >>> - EXTRA_CFLAGS/EXTRA_LDFLAGS are prefered in command line >> >>> to add flags to the default ones >> >>> >> >>> I'm not opposed to add EXTRA_LDLIBS in addition to LDLIBS, >> >>> keeping a compatibility with existing application Makefiles. >> >> >> >> The docs for DPDK 28.3.6 states they can be used for both command >>line >> >>and >> >> Makefile, so I think I like the current solution unless everyone >>wants >> >>it >> >> as you suggested. >> >> >> >> >> >>>>http://dpdk.readthedocs.org/en/v2.0.0/prog_guide/dev_kit_build_system.h >>>>tm >> >>l >> > >> > From the link you have sent: >> > >> >- About CFLAGS: >> > >> >"28.3.4. Variables that Can be Set/Overridden in a Makefile Only >> >[...] >> >CFLAGS: Flags to use for C compilation. The user should use += to >>append >> >data in this variable." >> > >> >nothing in 28.3.6 >> > >> > >> >- About EXTRA_CFLAGS: >> > >> >nothing in 28.3.4 >> > >> >"28.3.6. Variables that Can be Set/Overridden by the User in a Makefile >> >or Command Line >> >[...] >> >EXTRA_CFLAGS: The content of this variable is appended after CFLAGS >>when >> >compiling." >> >> The point was that EXTRA_XXX can be used for command line and Makefile >>as >> it was pointed out in a previous email the assumption was EXTRA_XXX was >> only for the command line. (Just to make sure we understood EXTRA_XXX >>was >> not just for command line options.) This was the reason I sent the link >>an >> to point out using EXTRA_XXX is a much cleaner method then allowing >> someone to modify what I believe is an internal variable. > >Just beware that setting EXTRA_* flags on the commandline can override >their >values in the makefiles, and cause unexpected compilation problems. >Therefore, >it tends to be best to avoid using the EXTRA_* variables for variables >essential >to compile. For example: putting "-g -O3" in EXTRA_CFLAGS is ok, as the >if the >useroverrides those with something else things should still work, but >putting >"-I/path/to/include" would not be. On the command line and makefile you should be using += and not just = or you run into this problem. > >/Bruce > >
