來自： http://blog.csdn.net/yangzhenping/article/details/50668445

?如何編譯和安裝libevent

編譯和安裝步驟：

$ apt-get install git
$ git clone https://github.com/libevent/libevent.git
$ cd libevent
$ apt-get install cmake
$ apt-get install libssl-dev
$ mkdir build && cd build
$ cmake .. # Default to Unix Makefiles.
$ make
$ make verify # (optional)
$ make install

一些學習文檔：

Fast portable non-blocking network programming with Libevent: http://www.wangafu.net/~nickm/libevent-book/
libevent-examples: https://github.com/jasonish/libevent-examples
multi-thread libevent: https://sourceforge.net/projects/libevent-thread/

針對第一個例子：

http://www.wangafu.net/~nickm/libevent-book/Ref1_libsetup.html
le.c內容：

#include <event2/event.h>

include <stdio.h>
define EVENT_LOG_DEBUG 0
define EVENT_LOG_MSG   1
define EVENT_LOG_WARN  2
define EVENT_LOG_ERR   3
/ Deprecated; see note at the end of this section /
define _EVENT_LOG_DEBUG EVENT_LOG_DEBUG
define _EVENT_LOG_MSG   EVENT_LOG_MSG
define _EVENT_LOG_WARN  EVENT_LOG_WARN
define _EVENT_LOG_ERR   EVENT_LOG_ERR
typedef void (event_log_cb)(int severity, const char msg);
void event_set_log_callback(event_log_cb cb);
static void discard_cb(int severity, const char msg)
{
    / This callback does nothing. */
}
static FILE logfile = NULL;
static void write_to_file_cb(int severity, const char msg)
{
    const char s;
    if (!logfile)
        return;
    switch (severity) {
        case _EVENT_LOG_DEBUG: s = "debug"; break;
        case _EVENT_LOG_MSG:   s = "msg";   break;
        case _EVENT_LOG_WARN:  s = "warn";  break;
        case _EVENT_LOG_ERR:   s = "error"; break;
        default:               s = "?";     break; / never reached */
    }
    fprintf(logfile, "[%s] %s\n", s, msg);
}
/ Turn off all logging from Libevent. /
void suppress_logging(void)
{
    event_set_log_callback(discard_cb);
}
/ Redirect all Libevent log messages to the C stdio file 'f'. /
void set_logfile(FILE f)
{
    logfile = f;
    event_set_log_callback(write_to_file_cb);
}
int main(int argc, char **argv)
{
FILE fp=fopen("/tmp/test.txt", "w+");
set_logfile(fp);
fclose(fp);
return 0;
}</pre>

$ gcc le.c -o le -levent 

$ ./le 

沒有輸出任何文本到/tmp/test.txt，因為main函數中沒有調用log，當然文中建議我們不要直接使用用戶提供的event_log_cb回調函數，因為這樣做是不安全的。 

有人翻譯了這本文檔，可以參考下： 

http://popozhu.github.io/page/7/ 

http://popozhu.github.io/page/6/ 





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