How do I read long lines from a text file in C++?

Question

I am using the following code for reading lines from a text-file. What is the best method for handling the case where the line is greater than the limit SIZE_MAX_LINE?

Answer 1

Don't use istream::getline(). It deals with naked character buffers and is therefor prone to errors. Better use std::getline(std::istream&,std::string&, char='\n') from the <string> header:

std::string line;

while(std::getline(xInFile, line)) {
    m_sStream.append(line);
    m_sStream.append('\n'); // getline() consumes '\n'
}

Answer 2

Since you're using C++ and iostream already, why not use std::string's getline function?

std::string acLine;
while(xInFile){
    std::getline(xInFile, acLine);
    // etc.
}

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And, use xInFile.good() to ensure eofbit and badbit and failbit are not set.

Answer 3

If you use the free function in string, you don't have to pass a max length. It also the uses C++ string type.