If you want to compile a source file including the ‘gpgme.h’ header file, you must make sure that the compiler can find it in the directory hierarchy. This is accomplished by adding the path to the directory in which the header file is located to the compilers include file search path (via the -I option).
However, the path to the include file is determined at the time the
source is configured. To solve this problem, gpgme ships with a small
gpgme-config that knows about the path to the
include file and other configuration options. The options that need
to be added to the compiler invocation at compile time are output by
the --cflags option to
gpgme-config. The following
example shows how it can be used at the command line:
gcc -c foo.c `gpgme-config --cflags`
Adding the output of ‘gpgme-config --cflags’ to the compiler command line will ensure that the compiler can find the GPGME header file.
A similar problem occurs when linking the program with the library.
Again, the compiler has to find the library files. For this to work,
the path to the library files has to be added to the library search
path (via the -L option). For this, the option
gpgme-config can be used. For
convenience, this option also outputs all other options that are
required to link the program with GPGME (in particular, the
‘-lgpgme’ option). The example shows how to link foo.o
with the GPGME library to a program
gcc -o foo foo.o `gpgme-config --libs`
Of course you can also combine both examples to a single command by
specifying both options to
gcc -o foo foo.c `gpgme-config --cflags --libs`
If you need to detect the installed language bindings you can use list them using:
or test for the availability using
gpgme-config --have-lang=python && echo 'Bindings for Pythons available'