Find Maximum Filename Length that Can Create on Linux using C++

In the Linux file systems, understanding the limitations and boundaries is important for efficient system management and development. One such aspect often overlooked is the maximum filename length permissible. For developers working with file I/O operations, knowing this limit is essential to prevent unexpected errors. This tutorial shows how to find maximum filename length that can create on Linux using C++.

The provided code snippet aims to determine the maximum filename length that can be created on a Linux system by iteratively attempting to create files with increasingly longer names. It starts by initializing a counter and an empty string to store the filename. Inside a continuous loop, the code appends a character (0) to the filename and attempts to create a file with that name. If successful, the counter is incremented, and the created file is immediately closed and deleted. This process continues until an attempt to create a file fails, at which point the loop breaks, and the count of successfully created files (representing the maximum filename length) is printed to the standard output.

#include <iostream>
#include <fcntl.h>
#include <unistd.h>

int main()
{
    unsigned long count = 0;
    std::string name;
    while (true) {
        name += "0";
        int fd = open(name.c_str(), O_CREAT, S_IWUSR);
        if (fd < 0) {
            break;
        }
        ++count;
        close(fd);
        unlink(name.c_str());
    }

    std::cout << count << std::endl;

    return 0;
}

Output example:

255