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poll/select: prevent busy-waiting 2012-05-21 Paolo Bonzini <bonzini@gnu.org> poll/select: prevent busy-waiting. SwitchToThread() only gives away the rest of the current time slice to another thread in the current process. So if the thread that feeds the file decscriptor we're polling is not in the current process, we get busy-waiting. * lib/poll.c: Use SleepEx(1, TRUE) instead of SwitchToThread(). Patch from Theodore Leblond. * lib/select.c: Split polling out of the loop that sets the output fd_sets. Check for zero result and loop if the wait timeout is infinite.
author Paolo Bonzini <bonzini@gnu.org>
date Mon, 21 May 2012 09:52:42 +0200
parents 0acb9b939828
children e542fd46ad6f
line wrap: on
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# ld-version-script.m4 serial 3
dnl Copyright (C) 2008-2012 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.

dnl From Simon Josefsson

# FIXME: The test below returns a false positive for mingw
# cross-compiles, 'local:' statements does not reduce number of
# exported symbols in a DLL.  Use --disable-ld-version-script to work
# around the problem.

# gl_LD_VERSION_SCRIPT
# --------------------
# Check if LD supports linker scripts, and define automake conditional
# HAVE_LD_VERSION_SCRIPT if so.
AC_DEFUN([gl_LD_VERSION_SCRIPT],
[
  AC_ARG_ENABLE([ld-version-script],
    AS_HELP_STRING([--enable-ld-version-script],
      [enable linker version script (default is enabled when possible)]),
      [have_ld_version_script=$enableval], [])
  if test -z "$have_ld_version_script"; then
    AC_MSG_CHECKING([if LD -Wl,--version-script works])
    save_LDFLAGS="$LDFLAGS"
    LDFLAGS="$LDFLAGS -Wl,--version-script=conftest.map"
    cat > conftest.map <<EOF
foo
EOF
    AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
                   [accepts_syntax_errors=yes], [accepts_syntax_errors=no])
    if test "$accepts_syntax_errors" = no; then
      cat > conftest.map <<EOF
VERS_1 {
        global: sym;
};

VERS_2 {
        global: sym;
} VERS_1;
EOF
      AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
                     [have_ld_version_script=yes], [have_ld_version_script=no])
    else
      have_ld_version_script=no
    fi
    rm -f conftest.map
    LDFLAGS="$save_LDFLAGS"
    AC_MSG_RESULT($have_ld_version_script)
  fi
  AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
])