将程序从 linux 移植到 solaris,使用 solarisstudio 12.3 构建它。
它有以下定义:
typedef std::list<ISocketMultiplexerJob *> CSocketJobs;
typedef CSocketJobs::iterator CJobCursor;
CSocketJobs m_socketJobs;
这个代码:
CSocketMultiplexer::CJobCursor
CSocketMultiplexer::nextCursor(CJobCursor cursor)
{
CLock lock(m_mutex);
CJobCursor j = m_socketJobs.end();
CJobCursor i = cursor;
while (++i != m_socketJobs.end()) {
if (*i != m_cursorMark) { // CRASHES HERE!!
j = i;
// move our cursor just past the job
m_socketJobs.splice(++i, m_socketJobs, cursor);
break;
}
}
return j;
}
它在上面指出的行崩溃,因为:
(dbx) print i
i = {
_C_node = (nil)
}
看起来“++i”迭代从列表中消失了,但是针对 m_socketJobs.end() 的测试没有看到它并让它通过。需要帮助调试,例如,如何以更能识别 c++ 的方式分析 dbx 中的 *i?
nextCursor() 的调用者在这个片段中,<>:
// collect poll entries
if (m_update) {
m_update = false;
pfds.clear();
pfds.reserve(m_socketJobMap.size());
CJobCursor cursor = newCursor();
CJobCursor jobCursor = nextCursor(cursor);
while (jobCursor != m_socketJobs.end()) {
ISocketMultiplexerJob* job = *jobCursor;
if (job != NULL) {
pfd.m_socket = job->getSocket();
pfd.m_events = 0;
if (job->isReadable()) {
pfd.m_events |= IArchNetwork::kPOLLIN;
}
if (job->isWritable()) {
pfd.m_events |= IArchNetwork::kPOLLOUT;
}
pfds.push_back(pfd);
}
jobCursor = nextCursor(cursor); //FATAL CALL
}
这是函数 newCursor():
CSocketMultiplexer::CJobCursor
CSocketMultiplexer::newCursor() {
CLock lock(m_mutex);
return m_socketJobs.insert(m_socketJobs.begin(), m_cursorMark);
}
我做了一些研究,发现 newCursor()/nextCursor() 排序工作和不工作......也许另一个线程正在损害上下文。在下面的示例中(嵌入在我的程序中)“CJobCursor c = newCursor();”的第一个 init 很健壮,我可以插入“c= nextCursor(c);”行 在我的程序中的任何地方,它都不会崩溃。但是下一个带有评论“BAD”的有缺陷,并在第二个 nexCursor() 调用中崩溃。我觉得这很有趣,但还没有解释。我认为我需要在整个程序中继续测试,因为上下文正在扼杀东西。你怎么看?
void
CSocketMultiplexer::serviceThread(void*)
{
std::vector<IArchNetwork::CPollEntry> pfds;
IArchNetwork::CPollEntry pfd;
CJobCursor c = newCursor();
CJobCursor j = nextCursor(c);
c = nextCursor(c);
c = nextCursor(c);
// service the connections
for (;;) {
CThread::testCancel();
// wait until there are jobs to handle
{
CLock lock(m_mutex);
while (!(bool)*m_jobsReady) {
m_jobsReady->wait();
}
}
// lock the job list
lockJobListLock();
lockJobList();
// collect poll entries
if (m_update) {
m_update = false;
pfds.clear();
pfds.reserve(m_socketJobMap.size());
CJobCursor cursor = newCursor(); //BAD, Ill-fated object
CJobCursor jobCursor = nextCursor(cursor);
c = nextCursor(c);
cursor = nextCursor(cursor); // SEGV's here
while (jobCursor != m_socketJobs.end()) {
ISocketMultiplexerJob* job = *jobCursor;
if (job != NULL) {
pfd.m_socket = job->getSocket();
pfd.m_events = 0;
if (job->isReadable()) {
pfd.m_events |= IArchNetwork::kPOLLIN;
}
if (job->isWritable()) {
pfd.m_events |= IArchNetwork::kPOLLOUT;
}
pfds.push_back(pfd);
}
c = nextCursor(c);
jobCursor = nextCursor(cursor);
}
c = nextCursor(c);
deleteCursor(cursor);
}