Re: $(file ...) function and other tools writing to the same file

[Martin Reinders]

On 14.03.16 14:43, Paul Smith wrote:
> On Mon, 2016-03-14 at 14:32 +0100, Martin Reinders wrote:
>>   $ cat Makefile
>>   all:
>>         /bin/echo "LINE FROM ECHO COMMAND" > file.txt
>>         $(file >>file.txt,LINE FROM FILE FUNCTION)
> 
>> I expected that the echo command writes one line to the file, and the
>> $(file ...) function appends another line. But as one can see, the 
>> file contains the output from the echo command only. It seems to me 
>> that the echo command is executed _after_ executing the $(file ...)
>> function.
> 
>> Perhaps I am misunderstanding something completely? Any insight is
>> highly appreciated.
> 
> The thing you're missing is that GNU make will always expand the ENTIRE
> recipe, before it starts ANY part of the recipe.  So, all variables and
> functions, including $(file ...), will be expanded first, then make will
> start to run the recipe lines.  So the $(file ...) function happens
> before the echo command, as you've seen.
> 

That makes perfect sense, thank you very much!