A pkg-config file for OpenJDK

[Omair Majid]

Hi,

Over in Fedora, we have received requests from developers asking that
compiling JNI programs and liking against the JVM be made easier [0]
[1]. Some of the current difficulties include that the VM type (server,
client) is not known by other programs and so they have to fall back to
guessing where the libjvm.so that they should link against is.

One standard approach on Linux for making linking against programs
easier is to use pkg-config [1] files.

A pkg-config file essentially describes the CFLAGS and LDFLAGS that need
to be passed to the compiler and the linker to compile and link a
program successfully, without knowing anything other than the name of
the program or library to compile/link against.

On Fedora/x86_64, such a file might look like (for OpenJDK 8):

> jdk=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.5.x86_64
> jre=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.5.x86_64/jre
> lib_arch=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.5.x86_64/jre/lib/amd64

> Name: java-1.8.0-openjdk
> Description: OpenJDK 8
> Version: 1.8.0.5
> Cflags: -I${jdk}/include -I${jdk}/include/linux
> Libs: -L${lib_arch} -L${lib_arch}/server -ljvm -ljava

Rather than doing something Fedora-specific, I would like to propose
carrying a template of this file upstream as part of the OpenJDK
project. Then, each distribution could modify it and change only the
bits that are specific to that distribution, and clients can rely on
having common or well-known names for everything else.

One nice-to-have feature would be keep this file somewhat generic, so
other JPackage-style non-OpenJDK JDKs could adapt it too. That's why I
have used `java-1.8.0-openjdk` as the name above, but I am open to
changing it to whatever the consensus is.

Does anyone else have any thoughts or comments about this?

Thanks,
Omair

[0] https://bugzilla.redhat.com/show_bug.cgi?id=449456
[1] https://bugzilla.redhat.com/show_bug.cgi?id=740762
[2] http://people.freedesktop.org/~dbn/pkg-config-guide.html

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