[ccache] Preprocessor stdout regression since v2.4

Joel Rosdahl joel at rosdahl.net
Sun Feb 20 07:22:05 MST 2011

On 2011-02-15 13:51, Mike Crowe wrote:
> It might not be expected for cpp to be a symlink to ccache but with
> ccache-v2.4 it did used to work so I found it easier for our build
> system just to symlink everything in the toolchain directory to ccache.
> Unfortunately between v2.4 (Debian Lenny version) and v3.1.4 the
> behaviour seems to have changed. When running the preprocessor ccache
> doesn't seem to realise that it should write the output to stdout.

Thanks for noting this.

The reason for the changed behaviour is that "ccache compiler header.h"
is a supported invocation (meaning: build a precompiled header from
header.h) in ccache 3.1 and higher, but it wasn't in ccache 2.4 (which
fell back to running the real compiler, i.e. cpp in this case).

So, don't symlink cpp to ccache. :-)

-- Joel

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