libev下載下傳使用(ubuntu)

從網上下載下傳解壓後，放在libev目錄下為例

 ./configure --prefix=$HOME/libev/usr/local

make

make install

 安裝好後：

test.c為另加入的，用來測試

test.c如下

// a single header file is required
#include <ev.h>
// for puts
#include <stdio.h>

// every watcher type has its own typedef'd struct
// with the name ev_TYPE
ev_io stdin_watcher;
ev_timer timeout_watcher;

// all watcher callbacks have a similar signature
// this callback is called when data is readable on stdin
static void stdin_cb(EV_P_ ev_io *w, int revents) {
    puts("stdin ready");
    // for one-shot events, one must manually stop the watcher
    // with its corresponding stop function.
    ev_io_stop(EV_A_ w);

    // this causes all nested ev_run's to stop iterating
    ev_break(EV_A_ EVBREAK_ALL);
}

// another callback, this time for a time-out
static void timeout_cb(EV_P_ ev_timer *w, int revents) {
    puts("timeout");
    // this causes the innermost ev_run to stop iterating
    ev_break(EV_A_ EVBREAK_ONE);
}

int main(void) {
    // use the default event loop unless you have special needs
    struct ev_loop *loop = EV_DEFAULT;

    // initialise an io watcher, then start it
    // this one will watch for stdin to become readable
    ev_io_init(&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
    ev_io_start(loop, &stdin_watcher);

    // initialise a timer watcher, then start it
    // simple non-repeating 5.5 second timeout
    ev_timer_init(&timeout_watcher, timeout_cb, 5.5, 0.);
    ev_timer_start(loop, &timeout_watcher);

    // now wait for events to arrive
    ev_run(loop, 0);

    // break was called, so exit
    return 0;
}

           

編譯、連結

gcc test.c -o test -I usr/local/include/ -L usr/local/lib/ -lev

執行

./test

如果5.5s内stdin沒有輸入，則列印timeout，否則列印stdin ready

一般編譯項目的步驟是:

./configure

make

make install

這個configure檔案當中存放的是shell腳本。

configure檔案

利用這個configure的腳本來檢視你的linux的運作環境,然後生成一個Makefile檔案

比如他檢查某個核心函數可不可用的時候,他就會先寫一個test.c 然後通過cat指令追加到這個test.c檔案當中。然後編譯運作，看看gcc是否報錯。如果不報錯說明該系統支援該核心函數。

進而将你的configure的情況重定向到config.log日志檔案當中。這裡面包含configure的結果，以及你configure時遇到的問題和你曾經的configure指令行曆史記錄

autotools包括

automake, autoconf

 以及其他一些工具,

automake

用于生成

Makefile

 的模闆

Makefile.in

，

autoconf

用于生成

configure

檔案。

+---------+
                    |         |
                    |         |
 Makefile.am +----> | automake| +-------> Makefile.in +-----+
                    |         |                             |
                    |         |                             |
                    |         |                             |
                    +---------+                             |
                                                            |
                    +---------+                             |
                    |         |                             |
                    |         |                             v
configure.ac +----> | autoconf| +-------> configure  +------+-----> Makefile
                    |         |
                    |         |
                    |         |
                    +---------+
           

用到./configure --prefix進行指定安裝

如果不指定prefix，則可執行檔案預設放在/usr/local/bin，庫檔案預設放在/usr/local/lib，配置檔案預設放在/usr/local/etc。其它的資源檔案放在/usr /local/share

編譯、連結gcc test.c -o test -I usr/local/include/ -L usr/local/lib/ -lev   使用了環境變量