1# =========================================================================== 2# http://www.gnu.org/software/autoconf-archive/ax_have_epoll.html 3# =========================================================================== 4# 5# SYNOPSIS 6# 7# AX_HAVE_EPOLL([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND]) 8# AX_HAVE_EPOLL_PWAIT([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND]) 9# 10# DESCRIPTION 11# 12# This macro determines whether the system supports the epoll I/O event 13# interface. A neat usage example would be: 14# 15# AX_HAVE_EPOLL( 16# [AX_CONFIG_FEATURE_ENABLE(epoll)], 17# [AX_CONFIG_FEATURE_DISABLE(epoll)]) 18# AX_CONFIG_FEATURE( 19# [epoll], [This platform supports epoll(7)], 20# [HAVE_EPOLL], [This platform supports epoll(7).]) 21# 22# The epoll interface was added to the Linux kernel in version 2.5.45, and 23# the macro verifies that a kernel newer than this is installed. This 24# check is somewhat unreliable if <linux/version.h> doesn't match the 25# running kernel, but it is necessary regardless, because glibc comes with 26# stubs for the epoll_create(), epoll_wait(), etc. that allow programs to 27# compile and link even if the kernel is too old; the problem would then 28# be detected only at runtime. 29# 30# Linux kernel version 2.6.19 adds the epoll_pwait() call in addition to 31# epoll_wait(). The availability of that function can be tested with the 32# second macro. Generally speaking, it is safe to assume that 33# AX_HAVE_EPOLL would succeed if AX_HAVE_EPOLL_PWAIT has, but not the 34# other way round. 35# 36# LICENSE 37# 38# Copyright (c) 2008 Peter Simons <simons@cryp.to> 39# 40# Copying and distribution of this file, with or without modification, are 41# permitted in any medium without royalty provided the copyright notice 42# and this notice are preserved. This file is offered as-is, without any 43# warranty. 44 45#serial 10 46 47AC_DEFUN([AX_HAVE_EPOLL], [dnl 48 ax_have_epoll_cppflags="${CPPFLAGS}" 49 AC_CHECK_HEADER([linux/version.h], [CPPFLAGS="${CPPFLAGS} -DHAVE_LINUX_VERSION_H"]) 50 AC_MSG_CHECKING([for Linux epoll(7) interface]) 51 AC_CACHE_VAL([ax_cv_have_epoll], [dnl 52 AC_LINK_IFELSE([dnl 53 AC_LANG_PROGRAM([dnl 54#include <sys/epoll.h> 55#ifdef HAVE_LINUX_VERSION_H 56# include <linux/version.h> 57# if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,45) 58# error linux kernel version is too old to have epoll 59# endif 60#endif 61], [dnl 62int fd, rc; 63struct epoll_event ev; 64fd = epoll_create(128); 65rc = epoll_wait(fd, &ev, 1, 0);])], 66 [ax_cv_have_epoll=yes], 67 [ax_cv_have_epoll=no])]) 68 CPPFLAGS="${ax_have_epoll_cppflags}" 69 AS_IF([test "${ax_cv_have_epoll}" = "yes"], 70 [AC_MSG_RESULT([yes]) 71$1],[AC_MSG_RESULT([no]) 72$2]) 73])dnl 74 75AC_DEFUN([AX_HAVE_EPOLL_PWAIT], [dnl 76 ax_have_epoll_cppflags="${CPPFLAGS}" 77 AC_CHECK_HEADER([linux/version.h], 78 [CPPFLAGS="${CPPFLAGS} -DHAVE_LINUX_VERSION_H"]) 79 AC_MSG_CHECKING([for Linux epoll(7) interface with signals extension]) 80 AC_CACHE_VAL([ax_cv_have_epoll_pwait], [dnl 81 AC_LINK_IFELSE([dnl 82 AC_LANG_PROGRAM([dnl 83#ifdef HAVE_LINUX_VERSION_H 84# include <linux/version.h> 85# if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19) 86# error linux kernel version is too old to have epoll_pwait 87# endif 88#endif 89#include <sys/epoll.h> 90#include <signal.h> 91], [dnl 92int fd, rc; 93struct epoll_event ev; 94fd = epoll_create(128); 95rc = epoll_wait(fd, &ev, 1, 0); 96rc = epoll_pwait(fd, &ev, 1, 0, (sigset_t const *)(0));])], 97 [ax_cv_have_epoll_pwait=yes], 98 [ax_cv_have_epoll_pwait=no])]) 99 CPPFLAGS="${ax_have_epoll_cppflags}" 100 AS_IF([test "${ax_cv_have_epoll_pwait}" = "yes"], 101 [AC_MSG_RESULT([yes]) 102$1],[AC_MSG_RESULT([no]) 103$2]) 104])dnl 105