+dnl Test whether mbrtowc returns the correct value on empty input.
+
+AC_DEFUN([gl_MBRTOWC_EMPTY_INPUT],
+[
+ AC_REQUIRE([AC_PROG_CC])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether mbrtowc works on empty input],
+ [gl_cv_func_mbrtowc_empty_input],
+ [
+ dnl Initial guess, used when cross-compiling or when no suitable locale
+ dnl is present.
+changequote(,)dnl
+ case "$host_os" in
+ # Guess no on AIX and glibc systems.
+ aix* | *-gnu*)
+ gl_cv_func_mbrtowc_empty_input="guessing no" ;;
+ *) gl_cv_func_mbrtowc_empty_input="guessing yes" ;;
+ esac
+changequote([,])dnl
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+ #include <wchar.h>
+ static wchar_t wc;
+ static mbstate_t mbs;
+ int
+ main (void)
+ {
+ return mbrtowc (&wc, "", 0, &mbs) == (size_t) -2;
+ }]])],
+ [gl_cv_func_mbrtowc_empty_input=no],
+ [gl_cv_func_mbrtowc_empty_input=yes],
+ [:])
+ ])
+])
+