如何实现“appendFile"功能? [英] How to implement "appendFile" function?

问题描述

我可以使用以下函数覆盖文本文件:

I can use the following function to overwrite a text file:

let writeFile ~filename:fn s =
let oc = open_out fn in
    output_string oc s;
    close_out oc ;;

但是，我不知道如何在文本文件中附加一行?

Howeve, i donot know how to append a line to a text file ?

推荐答案

您可以将附加模式标志 Open_append 传递给 open_out_gen 函数:

You could pass additional mode flag Open_append to open_out_gen function:

let _ =
    let oc = open_out_gen [Open_creat; Open_text; Open_append] 0o640 "a.txt" in
    output_string oc "append\n";
    close_out oc

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