check if an enum can set its underlying type

git-svn-id: https://svn.r-project.org/R/trunk@87765 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: ripley

configure

@@ -49635,6 +49635,51 @@ printf "%s\n" "#define HAVE_WORKING_SIGACTION 1" >>confdefs.h
   fi
 
 
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the base type of an enum can be specified" >&5
+printf %s "checking whether the base type of an enum can be specified... " >&6; }
+if test ${r_cv_enum_type+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if test "$cross_compiling" = yes
+then :
+  r_cv_enum_type=no
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+
+typedef enum :int { FALSE = 0, TRUE } Rboolean;
+
+int main(void) {
+     return 0;
+}
+
+
+_ACEOF
+if ac_fn_c_try_run "$LINENO"
+then :
+  r_cv_enum_type=yes
+else case e in #(
+  e) r_cv_enum_type=no ;;
+esac
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext ;;
+esac
+fi
+ ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $r_cv_enum_type" >&5
+printf "%s\n" "$r_cv_enum_type" >&6; }
+if test "x${r_cv_enum_type}" = xyes; then
+
+printf "%s\n" "#define HAVE_ENUM_BASE_TYPE 1" >>confdefs.h
+
+fi
+
+
 if test x${use_internal_tzcode} = xdefault; then
 case "${host_os}" in
    darwin*)

configure.ac

@@ -2273,6 +2273,11 @@ R_FUNC_LOG1P
 R_FUNC_FTELL
 R_FUNC_SIGACTION
 
+dnl setting the size of an 'enum' is a C23 addition,
+dnl also supported in some versions of clang.
+dnl GCC only supports it in a C23 mode.
+R_ENUM_BASE_TYPE
+
 if test x${use_internal_tzcode} = xdefault; then
 case "${host_os}" in
    darwin*)

m4/R.m4

@@ -5437,6 +5437,25 @@ int main(void) {
                [r_cv_C99=no])])
 ])# R_C90
 
+AC_DEFUN([R_ENUM_BASE_TYPE],
+[AC_CACHE_CHECK([whether the base type of an enum can be specified], [r_cv_enum_type],
+[AC_RUN_IFELSE([AC_LANG_SOURCE([[
+
+typedef enum :int { FALSE = 0, TRUE } Rboolean;
+
+int main(void) {
+     return 0;
+}
+
+]])],
+               [r_cv_enum_type=yes],
+               [r_cv_enum_type=no],
+               [r_cv_enum_type=no])])
+if test "x${r_cv_enum_type}" = xyes; then
+  AC_DEFINE(HAVE_ENUM_BASE_TYPE, 1, [Define if enum can set its base type.])
+fi
+])# R_ENUM_BASE_TYPE
+
 ### Local variables: ***
 ### mode: outline-minor ***
 ### outline-regexp: "### [*]+" ***

src/gnuwin32/fixed/h/config.h

@@ -278,6 +278,9 @@
 /* Define to 1 if you have the <elf.h> header file. */
 /* #undef HAVE_ELF_H */
 
+/* Define if enum can set its base type. */
+#define HAVE_ENUM_BASE_TYPE 1
+
 /* Define to 1 if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H 1
 

src/include/config.h.in

@@ -263,6 +263,9 @@
 /* Define to 1 if you have the <elf.h> header file. */
 #undef HAVE_ELF_H
 
+/* Define if enum can set its base type. */
+#undef HAVE_ENUM_BASE_TYPE
+
 /* Define to 1 if you have the <errno.h> header file. */
 #undef HAVE_ERRNO_H