在上篇文章中，我们写了如下测试脚本：
<?php
function task($n, $arg)
{
echo "coroutine [$n] create" . PHP_EOL;
Study\Coroutine::yield();
echo "coroutine [$n] be resumed" . PHP_EOL;
}
echo "main coroutine" . PHP_EOL;
Study\Coroutine::create('task', 1, 'a');
echo "main coroutine" . PHP_EOL;
Study\Coroutine::create('task', 2, 'b');
echo "main coroutine" . PHP_EOL;
Study\Coroutine::resume(1);
echo "main coroutine" . PHP_EOL;
Study\Coroutine::resume(2);
echo "main coroutine" . PHP_EOL;我们的协程任务函数task有一个参数$n，它是用来接收协程id的。很显然，这是不友好的。我们在开发的时候肯定不可能这样做对吧。所以我们需要提供一个接口来获取当前协程的id。
我们在study_coroutine_util.cc中进行实现：
PHP_METHOD(study_coroutine_util, getCid)
{
Coroutine* co = Coroutine::get_current();
RETURN_LONG(co->get_cid());
}然后注册这个函数：
PHP_ME(study_coroutine_util, getCid, arginfo_study_coroutine_void, ZEND_ACC_PUBLIC | ZEND_ACC_STATIC)然后编译、安装：
make clean && make && make install编写如下脚本进行测试：
<?php
function task($arg)
{
$cid = Study\Coroutine::getCid();
echo "coroutine [{$cid}] create" . PHP_EOL;
Study\Coroutine::yield();
echo "coroutine [{$cid}] create" . PHP_EOL;
}
echo "main coroutine" . PHP_EOL;
Study\Coroutine::create('task', 'a');
echo "main coroutine" . PHP_EOL;
Study\Coroutine::create('task', 'b');
echo "main coroutine" . PHP_EOL;
Study\Coroutine::resume(1);
echo "main coroutine" . PHP_EOL;
Study\Coroutine::resume(2);
echo "main coroutine" . PHP_EOL;执行脚本：
~/codeDir/cppCode/study # php test.php
main coroutine
coroutine [1] create
main coroutine
coroutine [2] create
main coroutine
coroutine [1] create
main coroutine
coroutine [2] create
main coroutine
~/codeDir/cppCode/study # OK，符合预期。
我们发现，我们的resume也是传递一个字面值，很明显，这个协程id应该是从Study\Coroutine::create返回的才对。所以我们改进Study\Coroutine::create这个接口：
PHP_METHOD(study_coroutine_util, create)
{
// 前面的代码没有改变
long cid = PHPCoroutine::create(&fcc, fci.param_count, fci.params);
RETURN_LONG(cid);
}我们返回了协程的id。
OK，我们重新编译、安装：
make clean && make && make install然后我们修改脚本：
<?php
function task($arg)
{
$cid = Study\Coroutine::getCid();
echo "coroutine [{$cid}] create" . PHP_EOL;
Study\Coroutine::yield();
echo "coroutine [{$cid}] create" . PHP_EOL;
}
echo "main coroutine" . PHP_EOL;
$cid1 = Study\Coroutine::create('task', 'a');
echo "main coroutine" . PHP_EOL;
$cid2 = Study\Coroutine::create('task', 'b');
echo "main coroutine" . PHP_EOL;
Study\Coroutine::resume($cid1);
echo "main coroutine" . PHP_EOL;
Study\Coroutine::resume($cid2);
echo "main coroutine" . PHP_EOL;然后执行：
~/codeDir/cppCode/study # php test.php
main coroutine
coroutine [1] create
main coroutine
coroutine [2] create
main coroutine
coroutine [1] create
main coroutine
coroutine [2] create
main coroutine
~/codeDir/cppCode/study # 符合预期。