If you want to write a library for distribution on most Un*x-like systems, chances are you'll want to use GNU Autotools. I have for a long time been curious how these tools work, and how the seemingly indecipherable syntaxes of @Makefile.am@ and @configure.ac@ were interpreted. And what is the relationship between @automake@, @autoconf@ and @aclocal@? The following online book is well worth the read: * "GNU Autoconf, Automake, and Libtool":https://sourceware.org/autobook/autobook/autobook_toc.html So far the general idea is the following: * aclocal generates an @aclocal.m4@ by scanning @configure.ac@ (from the @man@ page) * autoconf is for generating @./configure@ which figures out the configuration of the installation system; while * automake is for generating a @Makefile.in@, a Makefile template A common pattern in C header files is the following: 
/* File: some-header.h */
#ifdef __cplusplus
extern "C" {
#endif

/* Contents of header file */

#ifdef __cplusplus
}
#endif
which allows the C code to be used from C++. The author suggests instead to have a common header file with the following @ifdef@ magic: 
/* File: common.h */
#ifdef __cplusplus
# define BEGIN_C_DECLS extern "C" {
# define END_C_DECLS }
#else
# define BEGIN_C_DECLS 
# define END_C_DECLS
#endif
And rewrite the above as 
/* File: some-header.h */
#include <common.h>
BEGIN_C_DECLS

/* Contents of header file */

END_C_DECLS