"rb +"与"rb +"之间的区别是什么?和"ab"在fopen()中? [英] What is the difference between "rb+" and "ab" in fopen()?

问题描述

在C语言中使用fopen()时，我不理解"ab"和"rb+"模式之间的区别.

I do not understand the difference between the "ab" and "rb+" modes when using fopen() in C.

为什么我要选择一个而不是另一个?

Why would I choose one instead of the other?

推荐答案

使用上面的模式说明符，文件将作为文本文件打开.在 为了以二进制文件形式打开文件，必须使用"b"字符 包含在模式字符串中.这个额外的"b"字符可以 被附加在字符串的末尾(因此进行以下操作) 复合模式:"rb"，"wb"，"ab"，"r+b，"w+b"，"a+b")或被插入 字母和"+"符号之间的混合模式("rb+"，"wb+"， "ab+").

With the mode specifiers above the file is open as a text file. In order to open a file as a binary file, a "b" character has to be included in the mode string. This additional "b" character can either be appended at the end of the string (thus making the following compound modes: "rb", "wb", "ab", "r+b", "w+b", "a+b") or be inserted between the letter and the "+" sign for the mixed modes ("rb+", "wb+", "ab+").

摘录自 fopen文档，我建议您在提出问题之前先阅读一下.它将为您提供有关可能的参数，返回值，类似函数等的大量信息.

From fopen documentation which I advise you read before asking questions. It will give you a lot of information about possible parameters, return values, similar functions etc.

同样，来自同一文档:

"a" = 附加:打开文件以在文件末尾输出.输出操作始终将数据写入文件的末尾，然后对其进行扩展.重新定位操作(fseek，fsetpos，rewind)将被忽略.如果该文件不存在，则会创建该文件.

"a" = append: Open file for output at the end of a file. Output operations always write data at the end of the file, expanding it. Repositioning operations (fseek, fsetpos, rewind) are ignored. The file is created if it does not exist.

"r+" = 读取/更新:打开文件进行更新(用于输入和输出).该文件必须存在.

"r+" = read/update: Open a file for update (both for input and output). The file must exist.

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