fopen函数中“a”的用法
c语言小白想请教大家一下。看到小甲鱼c语言的文件教学视频中有一句话不是很理解。若要向已存在的文件追加信息，只能用“a”方式打开文件，但此时文件必须存在，否则会出错。可是查阅了一些资料，“a”在文件不存在时不是会新建文件嘛，有点迷惑{:5_99:}问题比较基础，谢谢大家的解答{:5_92:} 不胜感激！ 实测才是王道 filename - file name to associate the file stream to
mode - null-terminated character string determining file access mode
File access
mode string Meaning Explanation Action if file
already exists Action if file
does not exist
"r" read Open a file for reading read from start failure to open
"w" write Create a file for writing destroy contents create new
"a" append Append to a file write to end create new
"r+" read extended Open a file for read/write read from start error
"w+" write extended Create a file for read/write destroy contents create new
"a+" append extended Open a file for read/write write to end create new
File access mode flag "b" can optionally be specified to open a file in binary mode. This flag has no effect on POSIX systems, but on Windows, for example, it disables special handling of '\n' and '\x1A'.
On the append file access modes, data is written to the end of the file regardless of the current position of the file position indicator.
File access mode flag "x" can optionally be appended to "w" or "w+" specifiers. This flag forces the function to fail if the file exists, instead of overwriting it. (C++17)
The behavior is undefined if the mode is not one of the strings listed above. Some implementations define additional supported modes (e.g. Windows). shooan 发表于 2020-10-29 12:06
filename - file name to associate the file stream to
mode - null-terminated character string determ ...
这里说的比较清楚了，如果文件不存在的话，会创建一个新的文件 wp231957 发表于 2020-10-29 11:32
实测才是王道
谢谢大佬！确实要实测一下！ wp231957 发表于 2020-10-29 11:32
实测才是王道
谢谢大佬，确实要实测一下！ shooan 发表于 2020-10-29 12:07
这里说的比较清楚了，如果文件不存在的话，会创建一个新的文件
谢谢回答！
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