how to express technical issues

The string is returned in a statically allocated buffer. It will be  overwritten by subsequent calls .
这个字符串通过静态分配的内存返回，它会被后来的调用覆盖。
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what's port numbers?
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To request for service from a server, an obvious method is designating a server
by it's process ID and a host ID.
However, process IDs are assigned chronologicaly by process creation time, so the client
can't know in advance the process ID of a particular server process on a host.
To resolve this problem, the client uses a port number to specify a particular service,and
the server process created for that service can use that port number to handle the client's request.
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