[makefiles] How to edit commands / use conditional statements

[AncientPC]

I want to run different compiler flags depending on which system I'm on (e.g. school machines or laptop).

However I can't get it to run correctly.



ifeq (`hostname`,machine.school.edu)
CC:= -I /lusr/opt/boost1_38/
else
CC:= -std=gnu++0x
endif


The conditional statement never evaluates true for some reason.

[Arndt]

I want to run different compiler flags depending on which system I'm on (e.g. school machines or laptop).

However I can't get it to run correctly.



ifeq (`hostname`,machine.school.edu)
CC:= -I /lusr/opt/boost1_38/
else
CC:= -std=gnu++0x
endif


The conditional statement never evaluates true for some reason.

I think the problem is that the backquote construction doesn't belong to 'make', so it will be comparing the strings "`hostname`" and "machine.school.edu", which are not equal. Backquotes work in commands, because then they are passed to the shell. You can do


ifeq ($(shell hostname),machine.school.edu)
CC:= -I /lusr/opt/boost1_38/
else
CC:= -std=gnu++0x
endif

[AncientPC]

I think the problem is that the backquote construction doesn't belong to 'make', so it will be comparing the strings "`hostname`" and "machine.school.edu", which are not equal. Backquotes work in commands, because then they are passed to the shell. You can do


ifeq ($(shell hostname),machine.school.edu)
CC:= -I /lusr/opt/boost1_38/
else
CC:= -std=gnu++0x
endif
That works perfectly, thanks!