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I need to execute some make rules conditionally, only if the Python installed is greater than a certain version (say 2.5).
I thought I could do something like executing:
python -c 'import sys; print int(sys.version_info >= (2,5))' and then using the output ('1' if ok, '0' otherwise) in a ifeq make statement.
In a simple bash shell script it's just:
MY_VAR=`python -c 'import sys; print int(sys.version_info >= (2,5))'` but that doesn't work in a Makefile.
Any suggestions? I could use any other sensible workaround to achieve this.
820
To store the output of a command in a variable, you can use the shell command substitution feature in the forms below: variable_name=$(command) variable_name=$(command [option ...] arg1 arg2 ...) OR variable_name='command' variable_name='command [option ...] arg1 arg2 ...'
Expanded assignment = defines a recursively-expanded variable. := defines a simply-expanded variable.
To use it, just set the list of variables to print on the command line, and include the debug target: $ make V="USERNAME SHELL" debug makefile:2: USERNAME = Owner makefile:2: SHELL = /bin/sh.exe make: debug is up to date. Now you can print variables by simply listing them on the command line.
Use the Make shell builtin like in MY_VAR=$(shell echo whatever)
me@Zack:~$make MY_VAR IS whatever me@Zack:~$ cat Makefile MY_VAR := $(shell echo whatever) all: @echo MY_VAR IS $(MY_VAR) If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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