strlen

基本解釋

The strlen() function returns the length of a string.
函數(shù)的作用是：返回字符串長度。
We can use this fact to write another version of strlen, which computes the length of a string.
如果要更詳細的了解，建議還是把這章細讀一遍。
When we call strlen, it returns the number of characters in a zero-terminated array of single-byte characters.
許多年來，許多人一直將字符串作為一系列單字節(jié)字符來進行編碼，并在結尾處加上0.
The strlen() call was there only to make sure the value is actually accessed....
如果在聲明中用表達式的結果對其賦值會導致解析錯誤。
BTW: if you want to call recv() with the maximal length of return_msg, please use sizeof(return_msg) instead of strlen(return_msg).
但是就是不明白為什么如果接受的長度大于了實際返回的長度就可能出現(xiàn)我上述的那種情況呢（好像不是所有的時候都那樣）！