分析linux下的编译环境

Libraries have been installed in:
/usr/local/libIf you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the `-LLIBDIR'
flag during linking and do at least one of the following:
- add LIBDIR to the `LD_LIBRARY_PATH' environment variable
during execution
- add LIBDIR to the `LD_RUN_PATH' environment variable
during linking
- use the `-Wl,-rpath -Wl,LIBDIR' linker flag
- have your system administrator add LIBDIR to `/etc/ld.so.conf'See any operating system documentation about shared libraries for
more information, such as the ld(1) and ld.so(8) manual pages.

#include <ev.h>
#include <stdio.h>ev_io stdin_watcher;
ev_timer timeout_watcher;static void stdin_cb(EV_P_ ev_io *w,int revents)
{
puts ("stdin ready");
ev_io_stop(EV_A_ w);
ev_break (EV_A_ EVBREAK_ALL);
}static void timeout_cb (EV_P_ ev_timer *w,int revents)
{
puts ("timeout");
ev_break( EV_A_ EVBREAK_ONE );
}int main(int argc,char* argv[])
{
struct ev_loop *loop = EV_DEFAULT; ev_io_init(&stdin_watcher,stdin_cb,,EV_READ);
ev_io_start (loop,&stdin_watcher); ev_timer_init (&timeout_watcher,timeout_cb,5.5,); // in document the last is 0. not 0,I don't know why yet
ev_timer_start (loop,&timeout_watcher); ev_run (loop,); return ;
}output:
root@debian:/home/xzc/cpp/test# gcc -o libev_hello libev_hello.c
/tmp/ccNN2QkE.o: In function `stdin_cb':
libev_hello.c:(.text+0x20): undefined reference to `ev_io_stop'
libev_hello.c:(.text+0x33): undefined reference to `ev_break'
/tmp/ccNN2QkE.o: In function `timeout_cb':
libev_hello.c:(.text+0x5a): undefined reference to `ev_break'
/tmp/ccNN2QkE.o: In function `main':
libev_hello.c:(.text+0x71): undefined reference to `ev_default_loop'
libev_hello.c:(.text+0xc9): undefined reference to `ev_io_start'
libev_hello.c:(.text+0x11f): undefined reference to `ev_timer_start'
libev_hello.c:(.text+0x133): undefined reference to `ev_run'
collect2: ld returned exit status