I'm writing a C program that outputs test results, and I'd like it to print them in color so it's easier to scan through the results. I initially just used ANSI color codes (per https://stackoverflow.com/a/23657072/4954731), but a code reviewer wanted it to be more terminal-independent and suggested using ncurses instead.
The problem with using ncurses is that the test results outputted by my C program are interspersed with other test results from bash scripts. Something like this:
Test Name | Result
------------------------------
1+1 == 2 | PASS <-- outputted by a C executable
!(!true) == true | PASS <-- outputted by a bash script
0+0 == 0 | PASS <-- outputted by a C executable
...
So I can't use a regular ncurses screen - I have to play nicely with other output.
The bash scripts use tput
and setaf
to print with color, but I'm not sure if there's a way to use these tools in a C context without directly finding and calling the tput
executable...
Is there some way I can do terminal-agnostic color printing in C without using ncurses?
Guess what, tput is actually part of the underlying ncurses C library!
Here's an example of printing colored text using tput. Don't forget to compile with -lncurses
.
#include <stdio.h>
#include <curses.h>
#include <term.h>
int main()
{
// first you need to initialize your terminal
int result = setupterm(0, 1, 0);
if (result != 0) {
return result;
}
printf("%-62.62s ", "1+1 == 2");
// set color to green. You can pass a different function instead
// of putchar if you want to, say, set the stderr color
tputs(tparm(tigetstr("setaf"), COLOR_GREEN), 1, putchar);
// set text to bold
tputs(tparm(tigetstr("bold")), 1, putchar);
// this text will be printed as green and bold
printf("PASS\n");
// reset text attributes
tputs(tparm(tigetstr("sgr0")), 1, putchar);
// now this text won't be green and bold
printf("Done\n");
}
As you can see, you can freely mix-and-match tput stuff with regular printf output. There's no need to create a curses screen.
More information about tputs
, tparm
, etc here: https://invisible-island.net/ncurses/man/curs_terminfo.3x.html
Here's a list of what tigetstr
capabilities your terminal may have available: https://invisible-island.net/ncurses/man/terminfo.5.html#h3-Predefined-Capabilities