如何编译和安装libevent

比眉伴天荒 2022-01-30 04:37 311阅读 0赞

# 如何编译和安装libevent #

##       编译和安装步骤： ##

##    $ 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      一些学习文档： ##

## Fast portable non-blocking network programming with Libevent: [http://www.wangafu.net/~nickm/libevent-book/][http_www.wangafu.net_nickm_libevent-book]   libevent-examples: [https://github.com/jasonish/libevent-examples][https_github.com_jasonish_libevent-examples]   multi-thread libevent: [https://sourceforge.net/projects/libevent-thread/][https_sourceforge.net_projects_libevent-thread]      针对第一个例子： ##

[http://www.wangafu.net/~nickm/libevent-book/Ref1\_libsetup.html][http_www.wangafu.net_nickm_libevent-book_Ref1_libsetup.html]  
le.c内容：

#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;
    }

$ gcc le.c -o le -levent  
$ ./le  
没有输出任何文本到/tmp/test.txt，因为main函数中没有调用log，当然文中建议我们不要直接使用用户提供的event\_log\_cb回调函数，因为这样做是不安全的。  
有人翻译了这本文档，可以参考下：  
http://popozhu.github.io/page/7/  
http://popozhu.github.io/page/6/

[http_www.wangafu.net_nickm_libevent-book]: http://www.wangafu.net/~nickm/libevent-book/
[https_github.com_jasonish_libevent-examples]: https://github.com/jasonish/libevent-examples
[https_sourceforge.net_projects_libevent-thread]: https://sourceforge.net/projects/libevent-thread/
[http_www.wangafu.net_nickm_libevent-book_Ref1_libsetup.html]: http://www.wangafu.net/~nickm/libevent-book/Ref1_libsetup.html