使用 sscanf 读取字符串的其余部分 [英] reading the remainder of a string with sscanf

问题描述

我正在尝试读取一个字符串，该字符串由一组数字后跟一个字符串组成，其中包含一些其他基本文本.

I'm trying to read a string which consists of a set of numbers followed by a string, wrapped with some other basic text.

换句话说，行的格式是这样的:

In other words, the format of the line is something like this:

Stuff<5,10,-5,8,"Test string here.">

天真地，我试过了:

sscanf(str,"Stuff<%d,%d,%d,%d,\"%s\">",&i1,&i2,&i3,&i4,str2);

但经过一些研究，我发现 %s 应该在遇到空白字符时停止解析.我找到了这个问题，但没有一个答案能解决我的问题have:字符串中可以包含任何字符，包括换行符和正确转义的引号.后者不是问题，如果我可以让 sscanf 将所有内容放在我提供的预分配缓冲区中的第一个引号之后，我可以自己去掉结尾.

But after some research I discovered %s is supposed to stop parsing when it gets to a whitespace character. I found this question, but none of the answers addresses the problem I have: the string could contain any character in it, including newline characters and properly escaped quotes. The latter is not a problem, if I can just get sscanf to put everything after the first quote in the pre-allocated buffer I provide, I can strip the end off myself.

但是我该怎么做呢?我不能使用 %[] 因为它需要一些东西来终止字符串，而我唯一想终止它的是空终止符.所以我想，嘿，我就用空终止符吧！"但是 %[\0] 使编译器脾气暴躁:

But how do I do this? I can't use %[] because it requires something in it to terminate the string, and the only thing I want to terminate it is the null terminator. So I thought, "Hey, I'll just use the null terminator!" But %[\0] made the compiler grumpy:

warning: no closing ‘]’ for ‘%[’ format
warning: embedded ‘\0’ in format
warning: no closing ‘]’ for ‘%[’ format
warning: embedded ‘\0’ in format

使用诸如 %*c 之类的东西也行不通，因为我不知道到底需要取多少个字符.我尝试传递 strlen(str) 因为它会小于那个，但是 sscanf 返回 4 并且什么都没有放入 str2，这表明也许因为长度太长它放弃了，没有打扰.

Using something like %*c won't work either, because I don't know exactly how many characters need to be taken. I tried passing strlen(str) since it will be less than that, but sscanf returns 4 and nothing is put into str2, suggesting that perhaps because the length was too long it gave up and didn't bother.

更新:我想我可以这样做:

Update: I guess I could do something like:

sscanf(str,"Stuff<%d,%d,%d,%d,\"%n",&i1,&i2,&i3,&i4,&n);
str2 = str+n;

推荐答案

您的更新似乎是一个不错的答案.在使用 sscanf 通过 i1 获取 i1 之后，我打算建议 strchr 找到第一个引号字符的位置i4.旁注，您应该始终检查 sscanf 的返回值以确保转换有效.这对于您建议的答案更为重要，因为如果前四次转换不成功，n 将保持未初始化状态.

Your update seems to be a good answer. I was going to suggest strchr to find the location of the first quote char, after using sscanf to get i1 thru i4. Side note, you should always check the return value from sscanf to make sure that the conversions worked. This is even more important with your suggested answer, since n will be left uninitialized if the first four conversions aren't successful.

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