From 7bf07872ae8175e7d0af589f31e96f67b5083032 Mon Sep 17 00:00:00 2001 From: ripley Date: Fri, 6 Sep 2024 09:04:19 +0000 Subject: [PATCH] expand comments git-svn-id: https://svn.r-project.org/R/trunk@87102 00db46b3-68df-0310-9c12-caf00c1e9a41 --- src/include/R_ext/RS.h | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/src/include/R_ext/RS.h b/src/include/R_ext/RS.h index 16a98184be..e001e92ce1 100644 --- a/src/include/R_ext/RS.h +++ b/src/include/R_ext/RS.h @@ -74,7 +74,22 @@ extern void R_chk_free(void *); /* S Like Fortran Interface */ /* These may not be adequate everywhere. Convex had _ prepending common - blocks, and some compilers may need to specify Fortran linkage */ + blocks, and some compilers may need to specify Fortran linkage. + + Note that this is an F77 interface, intended only for valid F77 + names of <= 6 ASCII characters (and no underscores) and there is an + implicit assumption that the Fortran compiler maps names to + lower-case (and 'x' is lower-case when called). + + The configure code has + + HAVE_F77_EXTRA_UNDERSCORE + Define if your Fortran compiler appends an extra_underscore to + external names containing an underscore. + + but that is not used here (and none of gfortran, flang-new nor + x86_64 ifx do so: earlier Intel x86 compilere might have). + */ #ifdef HAVE_F77_UNDERSCORE # define F77_CALL(x) x ## _