These functions must be called after the stream has been opened(obviously, since each requires a valid file pointer as its first argument) but before any other operation is performed on the stream.

这些函数必须在流打开后被调用（很明显，因为每个函数都需要一个有效的文件指针作为它的第一个参数），但是在对流有任何操作之前。

youdao

These functions must be called after the stream has been opened(obviously, since each requires a valid file pointer as its first argument) but before any other operation is performed on the stream.

这些函数必须在流打开后被调用（很明显，因为每个函数都需要一个有效的文件指针作为它的第一个参数），但是在对流有任何操作之前。

youdao