# Makefile config



## dennylin93 (Jun 6, 2009)

I'm editing a Makefile, and I came across this problem:


```
COMMENT=        PHP Scripting Language
COMMENT?=       Version 2.2.x of Apache web server with ${WITH_MPM:L} MPM.
```

The first line is from php5/Makefile, and the second line is from www/apache22/Makefile. Why does the second line have a "?" after COMMENT?


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## graudeejs (Jun 6, 2009)

?= indicates, that if variable is not defined, Makefile will define it

It's like using *CC?=gcc*
if CC is not defined (usually it's defined to system default compiler aka cc)


I find it weird to have comment?= in Makefile


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## Carpetsmoker (Jun 10, 2009)

> I find it weird to have comment?= in Makefile



It is useful for master/slave ports.


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