gistfile1.txt

# Force not to use eventfd
AC_ARG_ENABLE([eventfd], [AS_HELP_STRING([--disable-eventfd], [disable eventfd [default=no]])],
    [disable_eventfd=yes], [disable_eventfd=no])

eventfd_headers="no"
eventfd_can_run="no"

if test "x$disable_eventfd" != "xyes"; then
    # Check if we have eventfd.h header file.
    AC_CHECK_HEADERS(sys/eventfd.h, [eventfd_headers=yes])

    AC_MSG_CHECKING([for sys/eventfd.h functionality])

    AC_RUN_IFELSE(
        [AC_LANG_PROGRAM([[#include <sys/eventfd.h>
          #include <assert.h>]],
        [[int fd = eventfd (0, 0); assert (fd != -1);]])],
        [eventfd_can_run=yes], [], eventfd_can_run=no)

    AC_MSG_RESULT([$eventfd_can_run])

    if test "x$eventfd_headers" = "xyes" -a "x$eventfd_can_run" = "xyes"; then
        AC_DEFINE(ZMQ_HAVE_EVENTFD, 1,[Have eventfd extension.])
    fi
fi