Re: Conditional build

[Paul D. Smith]

%% "Andrew Small" <address@hidden> writes:

  as> I need to switch a build between for ROM and RAM.
  as> At the moment, I have a line near the top of the file:
  as> RUNFROMFLASH=yes

  as> and then:
  as> ifeq ($(RUNFROMFLASH),yes)
  as> # Run from Flash configuration files
  as> PROGNAME = flashweb
  as> NG_DEF += ,RTE_FLASH
  as> OBJS += hwsetup.$(NGOEXT) sections.$(NGOEXT)
  as> endif

  as> a sub-makefile also switches the linker sections between ROM & RAM
  as> depending on the value of RUNFROMFLASH.

  as> This is OK, but I'd rather it was streamlined so that the makefile
  as> itself did not need modifying to switch between build options.

Why not just run:

    make RUNFROMFLASH=no

?

  as> I tried prepending the .mk file with:
  as> rom:
  as>     RUNFROMFLASH=yes
  as>     all

  as> ram:
  as>     RUNFROMFLASH=no
  as>     all

Er... No.

The stuff after the TAB has to be _shell_ commands, not make commands.
That text is handed off to the shell as a shell script to be run.  You
could write it like this:

    rom:
            $(MAKE) RUNFROMFLASH=yes all

    ram:
            $(MAKE) RUNFROMFLASH=no all

Or, you could use target-specific variables and avoid the need to invoke
make recursively.


See the GNU make manual for info on how to invoke make, how to write
rules, etc.

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