CODEWITHSUNDEEP
c++consolecursorcursor-positiontui
Rikardo Koder
Rikardo Koder

Reputation: 672

Simple and portable method for managing console cursors action in C++

When dealing with console input (stdin,std::cin) is there a portable way in C++ to manage the various actions that a user may perform like:

  1. Backspace/Delete
  2. List item
  3. Left/Right arrow keys (moving cursor back/forth insert text)

For example in windows when using std::cin (eg: std::cin >> s;), it allows for arrow keys, however when using the same bit of code on linux, the arrow keys are assumed as part of the input, the cursor is not moved around.

I know of various TUI frameworks like curses and ncurses that provide such functionality however they are more than what is required.

I'm hoping there's a simple solution based on the standard libraries, or even a lightweight open source library that might have a std::getline like feature that is portable across the more popular OSes.

Upvotes: 1

Views: 823

Answers (2)

jhole
jhole

Reputation: 4236

readline is a good choice for Linux, but it's GPL! I use the following code to compile on Windows and Linux:

#ifdef USE_READLINE
    #include <readline/readline.h>
    #include <readline/history.h>
#endif
...
void getline(char *buf)
{
    #ifdef USE_READLINE
            char *tmp;
            tmp = readline(PROMPT);
            if(strncmp(tmp, buf, MAXLENGTH)) add_history(tmp);      // only add new content
            strncpy(buf, tmp, MAXLENGTH);
            buf[MAXLENGTH]='\0';    
            free(tmp);
    #else
            std::cout<<PROMPT;
            std::cin.get(buf,MAXLENGTH);
            std::cin.ignore(); // delete CR
    #endif
}

Upvotes: 0

James Kanze
James Kanze

Reputation: 154027

Things like backspace and delete are typically handled by the system; when you read from a terminal, you only get the input when the user presses enter.

What the system does is usually fairly limited. In particular, I don't know of any that do things like file name completion. If more than what the system does is desired, I would recommend looking into the readline library, used by many GNU programs (bash, gdb, etc.). It's available separately from the applications which use it. (Two small warnings: I don't know how good its support is for native Windows, and I'm not sure which license it is under: GPL or LGPL.)

Upvotes: 1

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