【原创】libevent使能多线程模式需要做些什么

[root@Betty WGET]# tar zxvf libevent-2.0.21-stable.tar.gz 
...
[root@Betty WGET]# cd libevent-2.0.21-stable

[root@Betty libevent-2.0.21-stable]# ll config*        
-rwxr-xr-x 1 sunfei sunfei  44826 11月 19 2012 config.guess
-rw-r--r-- 1 sunfei sunfei  11968 11月 19 2012 config.h.in
-rwxr-xr-x 1 sunfei sunfei  35454 11月 19 2012 config.sub
-rwxr-xr-x 1 sunfei sunfei 504592 11月 19 2012 configure
-rw-r--r-- 1 sunfei sunfei  21849 11月 18 2012 configure.in
[root@Betty libevent-2.0.21-stable]#

[root@Betty libevent-2.0.21-stable]# vi README 

0. BUILDING AND INSTALLATION (Briefly)

$ ./configure
$ make
$ make verify   # (optional)
$ sudo make install
...

[root@Betty libevent-2.0.21-stable]# ./configure --help
`configure' configures this package to adapt to many kinds of systems.

Usage: ./configure [OPTION]... [VAR=VALUE]...

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.  See below for descriptions of some of the useful variables.

Defaults for the options are specified in brackets.

Configuration:
  -h, --help              display this help and exit
      --help=short        display options specific to this package
      --help=recursive    display the short help of all the included packages
  -V, --version           display version information and exit
  -q, --quiet, --silent   do not print `checking ...' messages
      --cache-file=FILE   cache test results in FILE [disabled]
  -C, --config-cache      alias for `--cache-file=config.cache'
  -n, --no-create         do not create output files
      --srcdir=DIR        find the sources in DIR [configure dir or `..']

Installation directories:
  --prefix=PREFIX         install architecture-independent files in PREFIX
                          [/usr/local]
  --exec-prefix=EPREFIX   install architecture-dependent files in EPREFIX
                          [PREFIX]

By default, `make install' will install all the files in
`/usr/local/bin', `/usr/local/lib' etc.  You can specify
an installation prefix other than `/usr/local' using `--prefix',
for instance `--prefix=$HOME'.

For better control, use the options below.

Fine tuning of the installation directories:
  --bindir=DIR            user executables [EPREFIX/bin]
  --sbindir=DIR           system admin executables [EPREFIX/sbin]
  --libexecdir=DIR        program executables [EPREFIX/libexec]
  --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
  --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
  --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
  --libdir=DIR            object code libraries [EPREFIX/lib]
  --includedir=DIR        C header files [PREFIX/include]
  --oldincludedir=DIR     C header files for non-gcc [/usr/include]
  --datarootdir=DIR       read-only arch.-independent data root [PREFIX/share]
  --datadir=DIR           read-only architecture-independent data [DATAROOTDIR]
  --infodir=DIR           info documentation [DATAROOTDIR/info]
  --localedir=DIR         locale-dependent data [DATAROOTDIR/locale]
  --mandir=DIR            man documentation [DATAROOTDIR/man]
  --docdir=DIR            documentation root [DATAROOTDIR/doc/PACKAGE]
  --htmldir=DIR           html documentation [DOCDIR]
  --dvidir=DIR            dvi documentation [DOCDIR]
  --pdfdir=DIR            pdf documentation [DOCDIR]
  --psdir=DIR             ps documentation [DOCDIR]

Program names:
  --program-prefix=PREFIX            prepend PREFIX to installed program names
  --program-suffix=SUFFIX            append SUFFIX to installed program names
  --program-transform-name=PROGRAM   run sed PROGRAM on installed program names

System types:
  --build=BUILD     configure for building on BUILD [guessed]
  --host=HOST       cross-compile to build programs to run on HOST [BUILD]

Optional Features:
  --disable-option-checking  ignore unrecognized --enable/--with options
  --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
  --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
  --disable-dependency-tracking  speeds up one-time build
  --enable-dependency-tracking   do not reject slow dependency extractors
  --enable-gcc-warnings   enable verbose warnings with GCC
  --disable-thread-support
                          disable support for threading   去使能多线程支持（锁相关）
  --disable-malloc-replacement
                          disable support for replacing the memory mgt
                          functions
  --disable-openssl       disable support for openssl encryption
  --disable-debug-mode    disable support for running in debug mode
  --disable-libevent-install, disable installation of libevent

  --disable-libevent-regress, skip regress in make check

  --enable-function-sections, make static library allow smaller binaries with --gc-sections

  --enable-shared[=PKGS]  build shared libraries [default=yes]
  --enable-static[=PKGS]  build static libraries [default=yes]
  --enable-fast-install[=PKGS]
                          optimize for fast installation [default=yes]
  --disable-libtool-lock  avoid locking (might break parallel builds)

Optional Packages:
  --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
  --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
  --with-pic[=PKGS]       try to use only PIC/non-PIC objects [default=use
                          both]
  --with-gnu-ld           assume the C compiler uses GNU ld [default=no]
  --with-sysroot=DIR Search for dependent libraries within DIR
                        (or the compiler's sysroot if not specified).

Some influential environment variables:
  CC          C compiler command
  CFLAGS      C compiler flags
  LDFLAGS     linker flags, e.g. -L<lib dir> if you have libraries in a
              nonstandard directory <lib dir>
  LIBS        libraries to pass to the linker, e.g. -l<library>
  CPPFLAGS    (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
              you have headers in a nonstandard directory <include dir>
  CPP         C preprocessor

Use these variables to override the choices made by `configure' or to help
it to find libraries and programs with nonstandard names/locations.

Report bugs to the package provider.
[root@Betty libevent-2.0.21-stable]#

[root@Betty libevent-2.0.21-stable]# ./configure
...
checking for the pthreads library -lpthreads... no                        -- 1
checking whether pthreads work without any flags... yes                   -- 2
checking for joinable pthread attribute... PTHREAD_CREATE_JOINABLE        -- 3
checking if more special flags are required for pthreads... no
checking size of pthread_t... 8
...
[root@Betty libevent-2.0.21-stable]# 


[root@Betty libevent-2.0.21-stable]# 
[root@Betty libevent-2.0.21-stable]# ll config* 
-rwxr-xr-x 1 sunfei sunfei  44826 11月 19 2012 config.guess
-rw-r--r-- 1 root   root    12603 8月  19 14:25 config.h          -- new
-rw-r--r-- 1 sunfei sunfei  11968 11月 19 2012 config.h.in
-rw-r--r-- 1 root   root   168882 8月  19 14:25 config.log        -- new
-rwxr-xr-x 1 root   root    65544 8月  19 14:25 config.status     -- new
-rwxr-xr-x 1 sunfei sunfei  35454 11月 19 2012 config.sub
-rwxr-xr-x 1 sunfei sunfei 504592 11月 19 2012 configure
-rw-r--r-- 1 sunfei sunfei  21849 11月 18 2012 configure.in
[root@Betty libevent-2.0.21-stable]#

[root@Betty libevent-2.0.21-stable]# vi config.log 
This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.

It was created by configure, which was
generated by GNU Autoconf 2.68.  Invocation command line was

  $ ./configure

## --------- ##
## Platform. ##
## --------- ##

hostname = Betty
uname -m = x86_64
uname -r = 2.6.32-358.el6.x86_64
uname -s = Linux
uname -v = #1 SMP Fri Feb 22 00:31:26 UTC 2013
...
## ----------- ##
## Core tests. ##
## ----------- ##
...
configure:3214: checking for gcc
configure:3230: found /usr/bin/gcc
configure:3241: result: gcc
configure:3470: checking for C compiler version
configure:3479: gcc --version >&5
gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-11)
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

configure:3490: $? = 0
configure:3479: gcc -v >&5
Using built-in specs.
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --ena
ble-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-
dssi --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre --enable-libgcj-multifile --enable-java-maintainer-mode --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib --with-ppl --wi
th-cloog --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.4.7 20120313 (Red Hat 4.4.7-11) (GCC)
configure:3490: $? = 0
...
configure:14625: checking for the pthreads library -lpthreads         -- 检测能否以 -lpthreads 引用 libpthreads.so 库
configure:14658: gcc -o conftest -g -O2 -Wall -fno-strict-aliasing    conftest.c -lpthreads -lrt  >&5
conftest.c: In function 'main':
conftest.c:121: warning: null argument where non-null required (argument 1)
conftest.c:122: warning: null argument where non-null required (argument 1)
conftest.c:122: warning: null argument where non-null required (argument 3)
conftest.c:120: warning: 'th' is used uninitialized in this function
/usr/bin/ld: cannot find -lpthreads                                   -- 结果发现不能
collect2: ld returned 1 exit status
configure:14658: $? = 1
configure: failed program was:
| /* confdefs.h */
| #define PACKAGE_NAME ""
| #define PACKAGE_TARNAME ""
| #define PACKAGE_VERSION ""
| #define PACKAGE_STRING ""
| #define PACKAGE_BUGREPORT ""
| #define PACKAGE_URL ""
| #define PACKAGE "libevent"
| #define VERSION "2.0.21-stable"
| #define NUMERIC_VERSION 0x02001500
| #define STDC_HEADERS 1
| #define HAVE_SYS_TYPES_H 1
| #define HAVE_SYS_STAT_H 1
| #define HAVE_STDLIB_H 1
| #define HAVE_STRING_H 1
| #define HAVE_MEMORY_H 1
| #define HAVE_STRINGS_H 1
| #define HAVE_INTTYPES_H 1
| #define HAVE_STDINT_H 1
| #define HAVE_UNISTD_H 1
| #define HAVE_DLFCN_H 1
| #define LT_OBJDIR ".libs/"
| #define HAVE_ZLIB_H 1
| #define HAVE_LIBZ 1
| #define HAVE_OPENSSL_BIO_H 1
| #define HAVE_OPENSSL 1
| #define STDC_HEADERS 1
| #define HAVE_FCNTL_H 1
| #define HAVE_STDARG_H 1
| #define HAVE_INTTYPES_H 1
| #define HAVE_STDINT_H 1
| #define HAVE_STDDEF_H 1
| #define HAVE_POLL_H 1
| #define HAVE_UNISTD_H 1
| #define HAVE_SYS_EPOLL_H 1
| #define HAVE_SYS_TIME_H 1
| #define HAVE_SYS_QUEUE_H 1
| #define HAVE_SYS_PARAM_H 1
| #define HAVE_SYS_IOCTL_H 1
| #define HAVE_SYS_SELECT_H 1
| #define HAVE_NETINET_IN_H 1
| #define HAVE_SYS_SOCKET_H 1
| #define HAVE_SYS_UIO_H 1
| #define HAVE_ARPA_INET_H 1
| #define HAVE_SYS_EVENTFD_H 1
| #define HAVE_SYS_MMAN_H 1
| #define HAVE_SYS_SENDFILE_H 1
| #define HAVE_SYS_WAIT_H 1
| #define HAVE_NETDB_H 1
| #define HAVE_SYS_STAT_H 1
| #define HAVE_SYS_SYSCTL_H 1
| #define HAVE_TAILQFOREACH 1
| #define HAVE_TIMERADD 1
| #define HAVE_TIMERCMP 1
| #define HAVE_TIMERCLEAR 1
| #define HAVE_TIMERISSET 1
| #define HAVE_DECL_CTL_KERN 1
| #define HAVE_DECL_KERN_RANDOM 1
| #define HAVE_DECL_RANDOM_UUID 1
| #define HAVE_DECL_KERN_ARND 0
| #define TIME_WITH_SYS_TIME 1
| #define HAVE_GETTIMEOFDAY 1
| #define HAVE_VASPRINTF 1
| #define HAVE_FCNTL 1
| #define HAVE_CLOCK_GETTIME 1
| #define HAVE_STRTOK_R 1
| #define HAVE_STRSEP 1
| #define HAVE_GETNAMEINFO 1
| #define HAVE_INET_NTOP 1
| #define HAVE_INET_PTON 1
| #define HAVE_SIGNAL 1
| #define HAVE_SIGACTION 1
| #define HAVE_STRTOLL 1
| #define HAVE_INET_ATON 1
| #define HAVE_PIPE 1
| #define HAVE_EVENTFD 1
| #define HAVE_SENDFILE 1
| #define HAVE_MMAP 1
| #define HAVE_SPLICE 1
| #define HAVE_GETEUID 1
| #define HAVE_GETEGID 1
| #define HAVE_GETPROTOBYNUMBER 1
| #define HAVE_SETENV 1
| #define HAVE_UNSETENV 1
| #define HAVE_PUTENV 1
| #define HAVE_SYSCTL 1
| #define HAVE_UMASK 1
| #define HAVE_GETADDRINFO 1
| #define SIZEOF_LONG 8
| #define HAVE_SETFD 1
| #define HAVE_SELECT 1
| #define HAVE_POLL 1
| #define HAVE_EPOLL_CTL 1
| #define HAVE_EPOLL 1
| #define HAVE_UINT64_T 1
| #define HAVE_UINT32_T 1
| #define HAVE_UINT16_T 1
| #define HAVE_UINT8_T 1
| #define HAVE_UINTPTR_T 1
| #define HAVE_FD_MASK 1
| #define SIZEOF_LONG_LONG 8
| #define SIZEOF_LONG 8
| #define SIZEOF_INT 4
| #define SIZEOF_SHORT 2
| #define SIZEOF_SIZE_T 8
| #define SIZEOF_VOID_P 8
| #define HAVE_STRUCT_IN6_ADDR 1
| #define HAVE_STRUCT_SOCKADDR_IN6 1
| #define HAVE_SA_FAMILY_T 1
| #define HAVE_STRUCT_ADDRINFO 1
| #define HAVE_STRUCT_SOCKADDR_STORAGE 1
| #define HAVE_STRUCT_IN6_ADDR_S6_ADDR32 1
| #define HAVE_STRUCT_IN6_ADDR_S6_ADDR16 1
| #define HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY 1
| /* end confdefs.h.  */
| #include <pthread.h>
| int
| main ()
| {
| pthread_t th; pthread_join(th, 0);
|                      pthread_attr_init(0); pthread_cleanup_push(0, 0);
|                      pthread_create(0,0,0,0); pthread_cleanup_pop(0);
|   ;
|   return 0;
| }
configure:14667: result: no
configure:14570: checking whether pthreads work without any flags             -- 检查能否无任何 flag 使用 pthreads （这里的用意不太明白）
configure:14658: gcc -o conftest -g -O2 -Wall -fno-strict-aliasing    conftest.c  -lrt  >&5
conftest.c: In function 'main':
conftest.c:121: warning: null argument where non-null required (argument 1)
conftest.c:122: warning: null argument where non-null required (argument 1)
conftest.c:122: warning: null argument where non-null required (argument 3)
conftest.c:120: warning: 'th' is used uninitialized in this function
configure:14658: $? = 0
configure:14667: result: yes
configure:14686: checking for joinable pthread attribute                     -- 检查 pthread 特性是否支持 joinable（注意，这里就变成了 pthread 而不再是 pthreads）
configure:14701: gcc -o conftest -g -O2 -Wall -fno-strict-aliasing    conftest.c  -lrt  >&5
configure:14701: $? = 0
configure:14707: result: PTHREAD_CREATE_JOINABLE
configure:14717: checking if more special flags are required for pthreads
configure:14724: result: no
configure:14813: checking size of pthread_t
configure:14818: gcc -o conftest -g -O2 -Wall -fno-strict-aliasing    conftest.c -lrt  >&5
configure:14818: $? = 0
configure:14818: ./conftest
configure:14818: $? = 0
configure:14835: result: 8
configure:15289: creating ./config.status
...

[root@Betty libevent-2.0.21-stable]# vi config.h

/* config.h.  Generated from config.h.in by configure.  */
/* config.h.in.  Generated from configure.in by autoheader.  */
...
/* Define if libevent should not be compiled with thread support */
/* #undef DISABLE_THREAD_SUPPORT */
...
/* Define if you have POSIX threads libraries and header files. */
/* #undef HAVE_PTHREAD */
/* Define if we have pthreads on this system */
#define HAVE_PTHREADS 1                                   -- 和 thread 有关的宏，只定义了这个
...
/* Define to necessary symbol if this constant uses a non-standard name on
   your system. */
/* #undef PTHREAD_CREATE_JOINABLE */
...
/* The size of `pthread_t', as computed by sizeof. */
#define SIZEOF_PTHREAD_T 8

[root@Betty libevent-2.0.21-stable]# make
test -d include/event2 || /bin/mkdir -p include/event2
/bin/sed -f ./make-event-config.sed < config.h > include/event2/event-config.hT
mv -f include/event2/event-config.hT include/event2/event-config.h
...

• 基于 make-event-config.sed 文件，对 config.h 进行 sed 替换处理后，得到 event2/event-config.hT 文件；
• 再将 event2/event-config.hT 强制变更为（覆盖） event2/event-config.h 。

[root@Betty libevent-2.0.21-stable]# vi make-event-config.sed

# Sed script to postprocess config.h into event-config.h. -- 这里说的很清楚了，用于将 config.h 处理为 event-config.h

1i                                  --指定 event-config.h 开始内容
/* event2/event-config.h
 *
 * This file was generated by autoconf when libevent was built, and post-
 * processed by Libevent so that its macros would have a uniform prefix.
 *
 * DO NOT EDIT THIS FILE.
 *
 * Do not rely on macros in this file existing in later versions.
 */

#ifndef _EVENT2_EVENT_CONFIG_H_
#define _EVENT2_EVENT_CONFIG_H_

$a

#endif /* event2/event-config.h */    -- 指定 event-config.h 最后内容

s/#define /#define _EVENT_/      -- 这里完成了 XXX 到 _EVENT_XXX 的替换
s/#undef /#undef _EVENT_/
s/#ifndef /#ifndef _EVENT_/

[root@Betty libevent-2.0.21-stable]# vi include/event2/event-config.h

/* event2/event-config.h
 *
 * This file was generated by autoconf when libevent was built, and post-
 * processed by Libevent so that its macros would have a uniform prefix.
 *
 * DO NOT EDIT THIS FILE.
 *
 * Do not rely on macros in this file existing in later versions.
 */

#ifndef _EVENT2_EVENT_CONFIG_H_
#define _EVENT2_EVENT_CONFIG_H_

/* config.h.  Generated from config.h.in by configure.  */
/* config.h.in.  Generated from configure.in by autoheader.  */
...
/* Define if libevent should not be compiled with thread support */
/* #undef _EVENT_DISABLE_THREAD_SUPPORT */
...
/* Define if you have POSIX threads libraries and header files. */
/* #undef _EVENT_HAVE_PTHREAD */
/* Define if we have pthreads on this system */
#define _EVENT_HAVE_PTHREADS 1
...
/* Define to necessary symbol if this constant uses a non-standard name on
   your system. */
/* #undef _EVENT_PTHREAD_CREATE_JOINABLE */
...
/* The size of `pthread_t', as computed by sizeof. */
#define _EVENT_SIZEOF_PTHREAD_T 8
...

#if defined(_EVENT_HAVE_PTHREADS) || defined(_EVENT_IN_DOXYGEN)
/** Sets up Libevent for use with Pthreads locking and thread ID functions.
    Unavailable if Libevent is not build for use with pthreads.  Requires
    libraries to link against Libevent_pthreads as well as Libevent.


    @return 0 on success, -1 on failure. */
int evthread_use_pthreads(void);
/** Defined if Libevent was built with support for evthread_use_pthreads() */
#define EVTHREAD_USE_PTHREADS_IMPLEMENTED 1

#endif