file descriptor linux c++

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

int main() {
    int file_desc = open("example.txt", O_RDONLY);

    if (file_desc == -1) {
        std::cout << "Error opening the file\n";
        return 1;
    }

    // Perform operations using file_desc

    close(file_desc);

    return 0;
}

1. #include <iostream>: Includes the input/output stream library for handling standard input and output.
2. #include <unistd.h>: Includes the Unix Standard function definitions, including open() and close() for file operations.
3. int main(): Entry point of the program.
4. int file_desc = open("example.txt", O_RDONLY);: Opens a file named "example.txt" in read-only mode (O_RDONLY) and stores the file descriptor in the variable file_desc.
5. if (file_desc == -1): Checks if there was an error opening the file. If the open() function returns -1, an error occurred.
6. std::cout << "Error opening the file\n";: Prints an error message to the standard output if there was an issue opening the file.
7. return 1;: Exits the program with a non-zero status, indicating an error occurred during file opening.
8. Operations using file_desc: Perform read/write operations or other file-related actions using the obtained file descriptor.
9. close(file_desc);: Closes the file associated with the file descriptor file_desc.
10. return 0;: Exits the program with a status of 0, indicating successful execution.