When working with legacy code or migrating from PL/I to C++, you may encounter certain PL/I compiler-specific extensions that are not supported in standard C++. These extensions can often be a challenge when trying to port code from one language to another.

In this blog post, we will discuss some common PL/I compiler-specific extensions and how you can handle them while working with C++. Let’s dive in!

1. Character Handling Extensions

PL/I provides several character handling extensions that are not available in standard C++. One such extension is the TRANSLATE function, which allows you to convert characters in a string to uppercase or lowercase. In C++, you can achieve the same functionality using the std::transform function from the <algorithm> header.

#include <algorithm>
#include <cctype>
#include <string>

std::string translate(const std::string& str, bool toUpper) {
    std::string result(str);
    std::transform(result.begin(), result.end(), result.begin(),
                   [=](unsigned char c) { return toUpper ? std::toupper(c) : std::tolower(c); });
    return result;
}

Here, we define a translate function that takes a string and a boolean flag indicating whether to convert the characters to uppercase or lowercase. We use std::transform along with a lambda function to perform the character conversion.

2. File Handling Extensions

PL/I provides file handling extensions that are not directly available in C++. One such extension is the ability to specify file access modes during file opening. In C++, you can achieve similar functionality using the std::fstream class from the <fstream> header.

#include <fstream>
#include <iostream>

void processFile(const std::string& filename) {
    std::fstream file(filename, std::ios::in | std::ios::binary);
    if (file.is_open()) {
        // File processing code here
    } else {
        std::cout << "Failed to open the file: " << filename << std::endl;
    }
}

In the above code snippet, we open the file using std::fstream and pass the desired file access mode as the second argument. Here, std::ios::in indicates that we want to open the file for reading, and std::ios::binary indicates binary mode.

Conclusion

While migrating from PL/I to C++, it’s crucial to be aware of the PL/I compiler-specific extensions and find equivalent solutions in C++. By understanding the differences between the two languages, you can effectively handle these extensions and ensure a smooth transition.

#programming #PLI #C++