Found the following significant warnings:
  ../inst/include/sfheaders/cast/sfg.hpp:189:3: warning: control reaches end of non-void function [-Wreturn-type]
  ../inst/include/sfheaders/cast/sfg.hpp:78:17: warning: control reaches end of non-void function [-Wreturn-type]
  ../inst/include/sfheaders/cast/sfg.hpp:103:17: warning: control reaches end of non-void function [-Wreturn-type]
  ../inst/include/sfheaders/cast/sfg.hpp:130:17: warning: control reaches end of non-void function [-Wreturn-type]
  ../inst/include/sfheaders/cast/sfg.hpp:157:17: warning: control reaches end of non-void function [-Wreturn-type]
  /home/hornik/tmp/R.check/r-devel-gcc/Work/build/Packages/geometries/include/geometries/utils/columns/columns.hpp:173:19: warning: control reaches end of non-void function [-Wreturn-type]
  /home/hornik/tmp/R.check/r-devel-gcc/Work/build/Packages/geometries/include/geometries/utils/columns/columns.hpp:103:19: warning: control reaches end of non-void function [-Wreturn-type]
  /home/hornik/tmp/R.check/r-devel-gcc/Work/build/Packages/geometries/include/geometries/utils/columns/columns.hpp:140:19: warning: control reaches end of non-void function [-Wreturn-type]
  /home/hornik/tmp/R.check/r-devel-gcc/Work/build/Packages/geometries/include/geometries/utils/sexp/sexp.hpp:35:3: warning: control reaches end of non-void function [-Wreturn-type]
  ../inst/include/sfheaders/df/sfc.hpp:165:17: warning: control reaches end of non-void function [-Wreturn-type]
  ../inst/include/sfheaders/df/sfc.hpp:183:17: warning: control reaches end of non-void function [-Wreturn-type]
  ../inst/include/sfheaders/sf/sf_utils.hpp:53:17: warning: control reaches end of non-void function [-Wreturn-type]
  /home/hornik/tmp/R.check/r-devel-gcc/Work/build/Packages/geometries/include/geometries/matrix/to_mat.hpp:413:17: warning: control reaches end of non-void function [-Wreturn-type]
See ‘/home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/sfheaders.Rcheck/00install.out’ for details.
* used C++ compiler: ‘g++-12 (Debian 12.2.0-10) 12.2.0’