ANSI escape codes not displaying correctly

Question

I have the following defines:

#define ANSI_COLOR_RED     "\e[31m"
#define ANSI_COLOR_GREEN   "\e[32m"
#define ANSI_COLOR_YELLOW  "\e[33m"
#define ANSI_COLOR_BLUE    "\e[34m"
#define ANSI_COLOR_MAGENTA "\e[35m"
#define ANSI_COLOR_CYAN    "\e[36m"
#define ANSI_COLOR_RESET   "\e[0m"

I then use these like so:

char *getStatusColour(eTaskState state) {
    switch (state) {
        case eRunning:
            return ANSI_COLOR_GREEN;
            break;
        case eReady:
            return ANSI_COLOR_YELLOW;
            break;
        case eBlocked:
            return ANSI_COLOR_RED;
            break;
        case eSuspended:
            return ANSI_COLOR_BLUE;
            break;
        case eDeleted:
            return ANSI_COLOR_RESET;
            break;
    }

    return ANSI_COLOR_RESET;
}

printf("%s TEST %s\n", getStatusColour(eRunning), ANSI_COLOR_RESET);

The terminal output, however, does not work (IE: No colours and where the colour "should" be, is an unknown character (IE: Something not displayable).

Any ideas why this would not be working?

EDIT

It should be noted I get some colours printing when I change to:

#define ANSI_COLOR_GREEN \e[32m\\]

But the text is truncated, and I'm not sure what the \\] does.

Not every output device supports ANSI escapes. Which one are you using? — Ross Ridge, May 13 '16 at 07:29
@RossRidge I'm using a terminal on UNIX with 256 colour support. — JosephGarrone, May 13 '16 at 07:30
@Ruud, no luck, that just prints `\e[32m` at the start of each line and `\e[0m` at the end. — JosephGarrone, May 13 '16 at 07:37
Have you tryed [this format](http://stackoverflow.com/a/3586005/4944425)? — Bob__, May 13 '16 at 07:40
The color goes IN the format string not as part of a format specifier. e.g. `printf ("ANSI_COLOR_RED %s\n", somestring);` — David C. Rankin, May 13 '16 at 07:42
@DavidC.Rankin would that not simply act the same as I have currently? — JosephGarrone, May 13 '16 at 07:45
Can you confirm with this minimal code: `printf("%s TEST %s\n", "\e[31m", "\e[0m");`; if this works the problem is in code that is not present in the question; if it does not work, then your terminal does not work. — Antti Haapala -- Слава Україні, May 13 '16 at 07:47
@JosephGarrone what about [this](https://ideone.com/L5Z9NE) slightly less minimal example? — Iskar Jarak, May 13 '16 at 07:56
then the problem is in the code that is not present in your question. Perhaps `eRunning` is uninitialized. — Antti Haapala -- Слава Україні, May 13 '16 at 07:57
eRunning is an enum. I'll investigate more tomorrow. Thanks all for suggestions. Worst case I can just move the print into the switch and duplicate code. — JosephGarrone, May 13 '16 at 07:58
note that you do not have a `default` case, so if the value is invalid, then color reset escape is returned. Perhaps you'd want to print an error in the `default`. — Antti Haapala -- Слава Україні, May 13 '16 at 08:08
Also you do not need `break` after `return` I guess, unless this is some funny arduino C. — Antti Haapala -- Слава Україні, May 13 '16 at 08:08

score 5 · Accepted Answer · answered May 13 '16 at 07:43

5

Notice that \e is not a standard escape code and may thus fail (behaviour is undefined!):

% gcc ansi.c -pedantic
ansi.c: In function ‘main’:
ansi.c:4:12: warning: non-ISO-standard escape sequence, '\e'
     printf("\e[1;32mfoobar");

Use \033 or \x1B instead.

answered May 13 '16 at 07:43

Antti Haapala -- Слава Україні

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I've tried with both `\033` and `\x1B` to no avail. But point noted, I won't use `\e` (I'm used to it from shell) – JosephGarrone May 13 '16 at 07:44
However, I tried your code and, well, **it works for me**. – Antti Haapala -- Слава Україні May 13 '16 at 07:45
2

Looks like it might be somewhere else in the pipeline then. I'm interfacing from an Arduino to `kermusb` on a UNIX terminal. – JosephGarrone May 13 '16 at 07:47

ANSI escape codes not displaying correctly

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