1 files changed, 87 insertions, 0 deletions
diff --git a/m4/c32rtomb.m4 b/m4/c32rtomb.m4
new file mode 100644
index 0000000..5073865
--- /dev/null
+++ b/m4/c32rtomb.m4
@@ -0,0 +1,87 @@
+# c32rtomb.m4 serial 6
+dnl Copyright (C) 2020-2023 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_C32RTOMB],
+[
+  AC_REQUIRE([gl_UCHAR_H_DEFAULTS])
+
+  AC_REQUIRE([gl_MBRTOC32_SANITYCHECK])
+
+  dnl Cf. gl_CHECK_FUNCS_ANDROID
+  AC_CHECK_DECL([c32rtomb], , ,
+    [[#ifdef __HAIKU__
+       #include <stdint.h>
+      #endif
+      #include <uchar.h>
+    ]])
+  if test $ac_cv_have_decl_c32rtomb = yes; then
+    dnl We can't use AC_CHECK_FUNC here, because c32rtomb() is defined as a
+    dnl static inline function on Haiku 2020.
+    AC_CACHE_CHECK([for c32rtomb], [gl_cv_func_c32rtomb],
+      [AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <stdlib.h>
+              #ifdef __HAIKU__
+               #include <stdint.h>
+              #endif
+              #include <uchar.h>
+            ]],
+            [[char buf[8];
+              return c32rtomb (buf, 0, NULL) == 0;
+            ]])
+         ],
+         [gl_cv_func_c32rtomb=yes],
+         [gl_cv_func_c32rtomb=no])
+      ])
+  else
+    gl_cv_func_c32rtomb=no
+  fi
+  if test $gl_cv_func_c32rtomb = no; then
+    HAVE_C32RTOMB=0
+  else
+    dnl When we override mbrtoc32, redefining the meaning of the char32_t
+    dnl values, we need to override c32rtomb as well, for consistency.
+    if test $HAVE_WORKING_MBRTOC32 = 0; then
+      REPLACE_C32RTOMB=1
+    fi
+    AC_CACHE_CHECK([whether c32rtomb return value is correct],
+      [gl_cv_func_c32rtomb_retval],
+      [
+        dnl Initial guess, used when cross-compiling.
+changequote(,)dnl
+        case "$host_os" in
+          # Guess no on AIX.
+          aix*) gl_cv_func_c32rtomb_retval="guessing no" ;;
+          # Guess yes otherwise.
+          *)    gl_cv_func_c32rtomb_retval="guessing yes" ;;
+        esac
+changequote([,])dnl
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <stddef.h>
+#ifdef __HAIKU__
+ #include <stdint.h>
+#endif
+#include <uchar.h>
+int main ()
+{
+  int result = 0;
+  if (c32rtomb (NULL, 0, NULL) != 1)
+    result |= 1;
+  return result;
+}]])],
+          [gl_cv_func_c32rtomb_retval=yes],
+          [gl_cv_func_c32rtomb_retval=no],
+          [:])
+      ])
+    case "$gl_cv_func_c32rtomb_retval" in
+      *yes) ;;
+      *) AC_DEFINE([C32RTOMB_RETVAL_BUG], [1],
+           [Define if the c32rtomb function has an incorrect return value.])
+         REPLACE_C32RTOMB=1 ;;
+    esac
+  fi
+])