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= How to enable ccache =

 * Audience: All users
 * Requires: MacPorts >=1.6.0

== Introduction ==

This HOWTO covers how to enable building with [http://ccache.samba.org ccache]. It is a compiler cache. It uses the gcc -E switch and a hash to detect when a compilation can be satisfied from cache. The effect is that packages frequently compile 5-10 times faster than they would otherwise.

== Installation ==

=== Step 1: '''Install ccache''' ===
    
{{{
$ sudo port install ccache
}}}

=== Step 2: '''Edit macports.conf''' ===
  
Open `/opt/local/etc/macports/macports.conf` in your favorite editor. Find the line
{{{
configureccache     no
}}}
and change it to
{{{
configureccache     yes
}}}

And you are done. From now on, MacPorts will use ccache for building.

== Configuration ==

Please note that cache files are stored in .ccache in your home directory. To see some statistics how useful ccache is for you and how many disk space it takes, use
{{{
$ ccache -s
}}}

If you believe ccache takes up to much disk space for you, there is the possibility to set a maximum by using something like
{{{
$ ccache -M 2G
}}}
This makes ccache occupy a maximum of 2 GiB disk space to store cached files.

If you want to free some space, do a cleanup with
{{{
$ ccache -c
}}}

== Optional Parts ==

=== '''Use ccache outside MacPorts''' ===

To use ccache also outside MacPorts you have to edit your PATH which is set in your `.profile` or `.bash_profile`.

First, locate the file you are using. If there is a `.bash_profile` edit this file, if there is only `.profile` you want to edit this.
    
There will be this line in there:
{{{
export PATH=/opt/local/bin:/opt/local/sbin:$PATH
}}}

Now add the ccache binary path `/opt/local/ccache/bin` in front of already existing paths:
{{{
export PATH=/opt/local/ccache/bin:/opt/local/bin:/opt/local/sbin:$PATH
}}}

'''Important:''' Reopen your Terminal afterwards.

If you now use commands like ''gcc'' they automatically go through ccache.

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