g ++变量名有长度限制吗？ [英] is there a length limit on g++ variable names?

问题描述

查看标题

和一些填充文字

处理最小正文的要求

p>

我希望你现在可以快乐地度过任意限制

解决方案

简答：

没有

长答案：

是，它必须足够小以至于能适应记忆，否则不适用。如果有内在的限制（我不相信有），它是如此巨大，你真的很难达到它。

其实，你有我非常好奇，所以我创建了下面的Python程序来生成代码：

 ＃！ / usr / bin / env python2.6 
 import sys; 
 cppcode =
 #include< iostream> 
 #include< cstdlib> 
 
 int main（int argc，char * argv []）
 {
 int％s = 0; 
 return 0; 
} 

 
 def longvarname（n）：
 str =x; 
 for xrange（n）：
 str = str +0; 
 return str; 
 
 def printcpp（n）：
 print cppcode％longvarname（n）; 
 
 if __name __ ==__ main__：
 if len（sys.argv）== 2：
 printcpp（int（sys.argv [1]））; 
  

使用所需的长度变量名称生成C ++代码。使用以下内容：

 
 ./gencpp.py 1048576> main.cpp 
 g ++ main.cpp -o main 
 

上面的代码没有问题（变量名的长度大约为1MB）。我尝试了一个技巧，但是我并没有对字符串构造这么聪明，所以我决定在gencpp.py花费太长时间时放弃。

无论如何，我非常怀疑gcc预先为变量名分配1MB。它纯粹以记忆为界。

see title

and some filler text

to deal with the requirement of minimum body text

i hope you're happy now arbitrary limits

解决方案

Short Answer:
No

Long Answer:
Yes, it has to be small enough that it will fit in memory, but otherwise no, not really. If there is a builtin limit (I don't believe there is) it is so huge you'd be really hard-pressed to reach it.

Actually, you got me really curious, so I created the following Python program to generate code:

#! /usr/bin/env python2.6
import sys;
cppcode="""
#include <iostream>
#include <cstdlib>

int main(int argc, char* argv[])
{
     int %s = 0;
     return 0;
}
"""

def longvarname(n):
    str="x";
    for i in xrange(n):
        str = str+"0";
    return str;

def printcpp(n):
    print cppcode % longvarname(n);

if __name__=="__main__":
    if len(sys.argv)==2:
        printcpp(int(sys.argv[1]));

This generates C++ code using the desired length variable name. Using the following:

./gencpp.py 1048576 > main.cpp
g++ main.cpp -o main

The above gives me no problems (the variable name is roughly 1MB in length). I tried for a gigabyte, but I'm not being so smart with the string construction, and so I decided to abort when gencpp.py took too long.

Anyway, I very much doubt that gcc pre-allocates 1MB for variable names. It is purely bounded by memory.

这篇关于g ++变量名有长度限制吗？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！