警告:ISO C ++禁止将字符串常量转换为'char *'[-Wwrite-strings] [英] warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]

问题描述

非常简单的代码会警告我.一些提示不是建设性的.警告是:

very simple code does warn me. Some hints are not constructive. Warning is:

ISO C ++禁止将字符串常量转换为'char *'[-Wwrite-strings]

ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]

我尝试过:

char const *q = "pin";
char const *r = "\n\r";
{
while(client.findUntil(*q, *r)) 

没有成功

原始代码:

while(client.findUntil("pin", "\n\r"))

推荐答案

ISO C ++禁止将字符串常量转换为'char *'[-Wwrite-strings]

ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]

while(client.findUntil("pin", "\n\r"))

警告表示您的程序格式错误.您没有显示声明，但是从上下文可以推断出 findUntil 的参数是 char * .您不得将字符串文字传递给此类函数.

The warning means that your program is ill-formed. You didn't show the declaration, but from context, we can deduce that the argument of findUntil is char*. You may not pass a string literal to such function.

它过去格式正确-但已过时-在C ++ 11之前将字符串文字传递为 char * .

It used to be well-formed - but deprecated - to pass a string literal as char* prior to C++11.

我尝试过:

char const *q = "pin";
char const *r = "\n\r";

这些本身是正确的，但是

These are correct by themselves, but

while(client.findUntil(*q, *r)) 

这没有任何意义.以前您尝试传递字符串，但是现在您通过字符指针间接访问，因此您传递了字符.除非该函数是模板，否则它可能无法工作.

This makes no sense. Previously your were attempting to pass a string, but now you indirect through the character pointer so you are passing a character. Unless the function is a template, this cannot possibly work.

findUntil(q，r)也不起作用，因为指向const的指针不会隐式转换为指向非const的指针.

findUntil(q, r) won't work either, because the pointers to const won't implicitly convert to pointers to non-const.

正确的解决方案是将字符串文字复制到可修改的数组中:

A correct solution is to copy the string literals into modifiable arrays:

char q[] = "pin";
char r[] = "\n\r";
{
    while(client.findUntil(q, r)) 

另一种方法是修复 findUntil 以接受指向const char的指针.然后，您可以使用字符串文字，因为它们可以转换为指向const char的指针.

Another is to fix findUntil to accept a pointer to const char instead. Then you can use string literals, since they can be converted to a pointer to const char.

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