Initial Survey of API Usage

Using a small Java tool that drives the gcc preprocessor and runs some specialized regex queries yields the following reports on actual usage of the macros, typedefs, variables and functions defined in various R header files: The usage counts were determine by scanning all CRAN source files, they may include false positives because this was done on a textual base only. The packages "SOD" and "Boom" were ignored because they contain many false positives.

• Native API stats of R.h
• Native API stats of Rinternals.h without USE_R_INTERNALS
• Native API stats of Rinternals.h with USE_R_INTERNALS
• Native API stats of all header files

I am not a lawyer, but please be aware that this is derived from the include files and may be covered by the same licenses, e.g.:

/*
 *  R : A Computer Language for Statistical Data Analysis
 *  Copyright (C) 1995, 1996  Robert Gentleman and Ross Ihaka
 *  Copyright (C) 1999-2015   The R Core Team.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation; either version 2.1 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, a copy is available at
 *  https://www.R-project.org/Licenses/
 */
/*
 *  R : A Computer Language for Statistical Data Analysis
 *  Copyright (C) 2006-2016  The R Core Team.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, a copy is available at
 *  https://www.R-project.org/Licenses/
 */