view m4/javaexec.m4 @ 16869:38e6d30d7e4d

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 8250f2777afc
children e542fd46ad6f
line wrap: on
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# javaexec.m4 serial 5
dnl Copyright (C) 2001-2003, 2006, 2009-2012 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.

# Prerequisites of javaexec.sh.
# gt_JAVAEXEC or gt_JAVAEXEC(testclass, its-directory)
# Sets HAVE_JAVAEXEC to nonempty if javaexec.sh will work.

AC_DEFUN([gt_JAVAEXEC],
[
  AC_MSG_CHECKING([for Java virtual machine])
  AC_EGREP_CPP([yes], [
#if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
  yes
#endif
], CLASSPATH_SEPARATOR=';', CLASSPATH_SEPARATOR=':')
  CONF_JAVA=
  HAVE_JAVA_ENVVAR=
  HAVE_GIJ=
  HAVE_JAVA=
  HAVE_JRE=
  HAVE_JVIEW=
  HAVE_JAVAEXEC=1
  if test -n "$JAVA"; then
    HAVE_JAVA_ENVVAR=1
    CONF_JAVA="$JAVA"
  else
    pushdef([AC_MSG_CHECKING],[:])dnl
    pushdef([AC_CHECKING],[:])dnl
    pushdef([AC_MSG_RESULT],[:])dnl
    AC_CHECK_PROG([HAVE_GIJ_IN_PATH], [gij], [yes])
    AC_CHECK_PROG([HAVE_JAVA_IN_PATH], [java], [yes])
    AC_CHECK_PROG([HAVE_JRE_IN_PATH], [jre], [yes])
    AC_CHECK_PROG([HAVE_JVIEW_IN_PATH], [jview], [yes])
    popdef([AC_MSG_RESULT])dnl
    popdef([AC_CHECKING])dnl
    popdef([AC_MSG_CHECKING])dnl
    ifelse([$1], , , [
      save_CLASSPATH="$CLASSPATH"
      CLASSPATH="$2"${CLASSPATH+"$CLASSPATH_SEPARATOR$CLASSPATH"}
      ])
    export CLASSPATH
    if test -n "$HAVE_GIJ_IN_PATH" \
       && gij --version >/dev/null 2>/dev/null \
       ifelse([$1], , , [&& {
         echo "$as_me:__oline__: gij $1" >&AS_MESSAGE_LOG_FD
         gij $1 >&AS_MESSAGE_LOG_FD 2>&1
       }]); then
      HAVE_GIJ=1
      CONF_JAVA="gij"
    else
      if test -n "$HAVE_JAVA_IN_PATH" \
         && java -version >/dev/null 2>/dev/null \
         ifelse([$1], , , [&& {
           echo "$as_me:__oline__: gij $1" >&AS_MESSAGE_LOG_FD
           java $1 >&AS_MESSAGE_LOG_FD 2>&1
         }]); then
        HAVE_JAVA=1
        CONF_JAVA="java"
      else
        if test -n "$HAVE_JRE_IN_PATH" \
           && (jre >/dev/null 2>/dev/null || test $? = 1) \
           ifelse([$1], , , [&& {
             echo "$as_me:__oline__: gij $1" >&AS_MESSAGE_LOG_FD
             jre $1 >&AS_MESSAGE_LOG_FD 2>&1
           }]); then
          HAVE_JRE=1
          CONF_JAVA="jre"
        else
          if test -n "$HAVE_JVIEW_IN_PATH" \
             && (jview -? >/dev/null 2>/dev/null || test $? = 1) \
             ifelse([$1], , , [&& {
               echo "$as_me:__oline__: gij $1" >&AS_MESSAGE_LOG_FD
               jview $1 >&AS_MESSAGE_LOG_FD 2>&1
             }]); then
            HAVE_JVIEW=1
            CONF_JAVA="jview"
          else
            HAVE_JAVAEXEC=
          fi
        fi
      fi
    fi
    ifelse([$1], , , [
      CLASSPATH="$save_CLASSPATH"
    ])
  fi
  if test -n "$HAVE_JAVAEXEC"; then
    ac_result="$CONF_JAVA"
  else
    ac_result="no"
  fi
  AC_MSG_RESULT([$ac_result])
  AC_SUBST([CONF_JAVA])
  AC_SUBST([CLASSPATH])
  AC_SUBST([CLASSPATH_SEPARATOR])
  AC_SUBST([HAVE_JAVA_ENVVAR])
  AC_SUBST([HAVE_GIJ])
  AC_SUBST([HAVE_JAVA])
  AC_SUBST([HAVE_JRE])
  AC_SUBST([HAVE_JVIEW])
])