AC_DEFUN([gl_FUNC_GLIBC_UNLOCKED_IO],
[
AC_DEFINE([USE_UNLOCKED_IO], 1,
[Define to 1 if you want getc etc. to use unlocked I/O if available.
Unlocked I/O can improve performance in unithreaded apps,
but it is not safe for multithreaded apps.])
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
AC_CHECK_DECLS_ONCE([clearerr_unlocked])
AC_CHECK_DECLS_ONCE([feof_unlocked])
AC_CHECK_DECLS_ONCE([ferror_unlocked])
AC_CHECK_DECLS_ONCE([fflush_unlocked])
AC_CHECK_DECLS_ONCE([fgets_unlocked])
AC_CHECK_DECLS_ONCE([fputc_unlocked])
AC_CHECK_DECLS_ONCE([fputs_unlocked])
AC_CHECK_DECLS_ONCE([fread_unlocked])
AC_CHECK_DECLS_ONCE([fwrite_unlocked])
AC_CHECK_DECLS_ONCE([getc_unlocked])
AC_CHECK_DECLS_ONCE([getchar_unlocked])
AC_CHECK_DECLS_ONCE([putc_unlocked])
AC_CHECK_DECLS_ONCE([putchar_unlocked])
])