Macro: vl_decl_wchar_max

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Synopsis

  `VL_DECL_WCHAR_MAX`

Version

  1.1 C_Support @ ac-archive-0.5.39

Author

  Ville Laurikari <vl@iki.fi>

Description

  Checks whether the system headers define WCHAR_MAX or not. If it is already defined, does nothing. Otherwise checks the size and signedness of `wchar_t', and defines WCHAR_MAX to the maximum value that can be stored in a variable of type `wchar_t'.

M4 Source Code

      AC_DEFUN([VL_DECL_WCHAR_MAX], [
        AC_CACHE_CHECK([whether WCHAR_MAX is defined], vl_cv_decl_wchar_max, [
          AC_TRY_COMPILE([
      #ifdef HAVE_WCHAR_H
      #include <wchar.h>
      #endif
      ],[WCHAR_MAX],[vl_cv_decl_wchar_max="yes"],[vl_cv_decl_wchar_max="no"])])
        if test $vl_cv_decl_wchar_max = "no"; then
          VL_CHECK_SIGN([wchar_t],
            [ wc_signed="yes"
              AC_DEFINE(WCHAR_T_SIGNED, 1, [Define if wchar_t is signed]) ],
            [ wc_signed="no"
              AC_DEFINE(WCHAR_T_UNSIGNED, 1, [Define if wchar_t is unsigned])], [
      #ifdef HAVE_WCHAR_H
      #include <wchar.h>
      #endif
      ])
          if test "$wc_signed" = "yes"; then
            AC_DEFINE(WCHAR_MAX, [(1L << (sizeof(wchar_t) * 8 - 1) - 1)], [
      Define to the maximum value of wchar_t if not already defined elsewhere])
          elif test "$wc_signed" = "no"; then
            AC_DEFINE(WCHAR_MAX, [(1L << (sizeof(wchar_t) * 8) - 1)])
          fi
        fi
      ])dnl