Get specific value of preprocessor macro

Question

In my build settings i have define some preprocessor macros

i.e. SANDBOX_ENV=1

I want to use the value of SANDBOX_ENV in my shell script.

I have tried echo "SANDBOX value is = ${GCC_PREPROCESSOR_DEFINITIONS}"

but its giving me all macros values like DEBUG=1 SANDBOX_ENV=1 COCOAPODS=1

I want to use value that is assigned to SANDBOX_ENV

Answer 1

Try this:

#!/bin/bash
GCC_PREPROCESSOR_DEFINITIONS="DEBUG=1 SANDBOX_ENV=1 COCOAPODS=1" 
# delete everything before our value ans stuff into TMPVAL
TMPVAL="${GCC_PREPROCESSOR_DEFINITIONS//*SANDBOX_ENV=/}" 
# remove everything after our value from TMPVAL and return it
TMPVAL="${TMPVAL// */}"
echo $TMPVAL;  #outputs 1 

HTH,

bovako

Answer 2

You should be able to parse it easily with awk or something, but here's how I'd do it:

echo $GCC_PREPROCESSOR_DEFINITIONS | grep -Po 'SANDBOX_ENV=\d+' | sed 's/SANDBOX_ENV=//'

In your echo context:

echo "SANDBOX value is $(echo $GCC_PREPROCESSOR_DEFINITIONS | grep -Po 'SANDBOX_ENV=\d+' | sed 's/SANDBOX_ENV=//')"

Basically I piped the contents of GCC_PREPROCESSOR_DEFINITIONS and grepped out the SANDBOX_ENV portion.

grep -P 

is to use the Perl regex \d+, because I don't like POSIX. Just a preference. Essentially what

grep -P 'SANDBOX_ENV=\d+' 

does is to find the line in the content piped to it that contains the string "SANDBOX_ENV=" and any number of digits succeeding it. If the value might contain alphanumerics you can change the \d for digits to \w for word which encompasses a-zA-Z0-9 and you get:

grep -Po 'SANDBOX_ENV=\w+'

The + just means there must be at least one character of the type specified by the character before it, including all succeeding characters that matches.

the -o (only-matching) in grep -Po is used to isolate the match so that instead of the entire line you just get "SANDBOX_ENV=1".

This output is then piped to the sed command where I do a simple find and replace where I replaced "SANDBOX_ENV=" with "", leaving only the value behind it. There are probably easier ways to do it like with awk, but you'll have to learn that yourself.

Answer 3

If you want to have something self contained within the Build Settings and you don't mind slight indirection, then:

1. Create User-Defined settings SANDBOX_ENV=1 (or whatever value you want)
2. In Preprocessor Macros, add SANDBOX_ENV=${SANDBOX_ENV}

In your shell, to test, do

echo ${SANDBOX_ENV}

With the User-Defined Settings, you'll still be able to modify the value for Build Configuration and Architecture. So, for example, you could make the Debug config be SANDBOX_ENV=0 and Release be SANDBOX_ENV=1.