ColrC  0.4.0
An easy to use C library for linux terminal colors/escape-codes.

Getting Started

ColrC (kuh·lr·see, feels like heresy) is a C library for terminal colors/escape-codes on linux.

There is also a command-line tool (colr tool) based on ColrC.

It is designed to be flexible and easy to use. Colors can be specified using defined names (RED, BLUE, etc.), 256-colors (ext(36)), RGB colors (rgb(0, 0, 55)), hex colors (hex(s), hex("#ff0000")), or known names ("aliceblue"). These colors can be used with fore() and back() to set the foreground/background colors (fore(RED), back(WHITE)). Styles are specified with their defined names (style(BRIGHT)).

Strings can be joined, replaced, colorized, and justified using a few functions/macros. fore(), back(), and style() are mostly optional and position doesn't matter.

Ownership in ColrC is easy to remember. Strings (char*) are yours, everything else belongs to ColrC. If you create a ColrC object with one of the Colr* macros to use inside of the colr* macros (notice the casing), it will be released. The resulting strings that are returned from the colr* macros will not be released. You must free() those.

If you use colr_print or colr_puts you won't have to manage the resulting string either.


You must include colr.h and compile colr.c along with your program.

#include "colr.h"
int main(void) {
// Simple usage:
char* s = colr("Hello from ColrC!", fore("blueviolet"), back(WHITE));
if (!s) return EXIT_FAILURE;
// Or just:
colr_puts(Colr("Hello again!", fore(rgb(255, 0, 0)), back("#ffff00")));
// Fancier functions:
char* s2 = colr_replace(
" ",
Colr("Good", fore(rgb(0, 0, 255)), back(RESET)),
Colr("bye", fore(CYAN), style(BRIGHT))
Colr("good luck", style(UNDERLINE))
if (!s2) return EXIT_FAILURE;

There are plenty of examples in the documentation, and on this page.


ColrC uses a couple glibc features, which may not be compatible with your system. Most linux distros are compatible.

The colr.h header defines _GNU_SOURCE if it's not already defined (see man feature_test_macros).

Be sure to include libm (the math library) when compiling:

gcc -std=c11 -c myprogram.c colr.c -o myexecutable -lm


The only two files that are needed to use ColrC are colr.h and colr.c.

Name Description
colr.h The interface to ColrC.
colr.c Where ColrC is implemented. This must be compiled/linked with your program.


You can also create a shared library ( for your system. Clone the repo and run the make target:

make libdebug
# Or, build it with no debug info and optimizations turned on:
make librelease

If you link the library (and libm), you will only need to include the header (colr.h):

gcc -std=c11 -c myprogram.c -o myexecutable -lm -lcolr

There are several make targets to help you build and install the library:

# Build a debian package for libcolr and install it:
make distdeb
sudo dpkg -i dist/libcolr-dev_latest_amd64.deb

If you don't want to use a debian package, you can run the included installer. The installer is interactive, and will let you choose where to install the library based on GCC's library search path. It will not overwrite existing files without confirmation:

# Build libcolr with debug info, and install it:
make libinstalldebug
# Build libcolr with debug info, and symlink/install it:
make liblinkdebug

Example Usage

For a full listing see the docs, but here are the main features in ColrC:

Name Purpose
colr Generates a colorized string.
Colr Generates a colorized ColorText, for use with other functions/macros.
colr_cat Concatenates strings and ColrC objects into a string.
Colr_cat Concatenates strings and ColrC objects into a ColorResult, for use with other functions/macros.
colr_join Generates a string by joining strings/ColrC-objects by another string/ColrC-object.
Colr_join Generates a ColorResult by joining strings/ColrC-objects by another string/ColrC-object, for use with other functions/macros.

When an allocated ColorArg/ColorText/ColorResult is used inside of a Colr/colr call it is automatically released. Strings produced by a Colr/colr call are managed by the user (you must free() them).

I've included an example that showcases some of these:

#include "colr.h"
int main(int argc, char** argv) {
// Print-related macros, using Colr() to build colorized text:
puts("\nColrC supports ");
", ",
Colr("basic", fore(WHITE)),
Colr("extended (256)", fore(ext(155))),
Colr("rgb", fore(rgb(155, 25, 195))),
Colr("hex", fore(hex("#ff00bb"))),
Colr("extended hex", fore(ext_hex("#ff00bb"))),
Colr("color names", fore("dodgerblue"), back("aliceblue")),
Colr("and styles.", style(BRIGHT))
"Strings and ",
Colr("colors", fore(LIGHTBLUE)),
" can be mixed in any order."
// Create a string, using colr(), instead of colr_puts() or colr_print().
char* mystr = colr("Don't want to print this.", style(UNDERLINE));
printf("\nNow I do: %s\n", mystr);
// Concatenate existing strings with ColrC objects.
// Remember that the colr macros will free ColrC objects, not strings.
// So I'm going to use the Colr* macros inside of this call (not colr*).
char* catted = colr_cat(
"Exhibit: ",
Colr("b", fore(BLUE)),
"\nThe ColorText/Colr was released."
// Create a ColorText, on the heap, for use with colr_cat(), colr_print(),
// or colr_puts().
ColorText* ctext = NULL;
if (argc == 1) {
ctext = Colr("<nothing>", fore(RED));
} else {
ctext = Colr(argv[1], fore(GREEN));
char* userstr = colr_cat("Argument: ", ctext);
// colr_cat() already called ColorText_free(ctext).
// Create a joined string (a "[warning]" label).
char* warning_label = colr_join(Colr("warning", fore(YELLOW)), "[", "]");
// Simulate multiple uses of the string.
for (int i = 1; i < 4; i++) printf("%s This is #%d\n", warning_label, i);
// Okay, now we're done with the colorized string.
// Colorize an existing string by replacing a word.
char* logtext = "[warning] This is an awesome warning.";
char* colorized = colr_replace(
Colr("warning", fore(YELLOW))
// Failed to allocate for new string?
if (!colorized) return EXIT_FAILURE;
// You have to free the resulting string.
// Or colorize an existing string by replacing a regex pattern.
colorized = colr_replace_re(
Colr("ok", style(BRIGHT)),
if (!colorized) return EXIT_FAILURE;
// Or maybe you want to replace ALL of the occurrences?
char* logtext2 = "[warning] This is an awesome warning.";
// There is also a colr_replace_re_all() if you'd rather use a regex pattern.
char* colorizedall = colr_replace_all(
Colr("WARNING", fore(YELLOW))
// Failed to allocate for new string?
if (!colorizedall) return EXIT_FAILURE;
// You have to free the resulting string.

Example Files

For all examples, check the documentation. Here is a table of the most common usage examples:

Name Example
Colr Colr_example.c
Colr_cat colr_cat_example.c
Colr_join colr_join_example.c
colr_cat colr_cat_example.c
colr_join colr_join_example.c
colr_replace colr_replace_example.c
colr_replace_all colr_replace_all_example.c
colr_replace_re colr_replace_re_example.c
colr_replace_re_all colr_replace_re_all_example.c
fore fore_example.c
back back_example.c
style style_example.c

There are examples for all of the main features in ColrC, and tools (like the snippet runner) you can play with if you clone the repo.


ColrC is the C version of Colr (a python library) and it's less-flexible cousin The programming styles vary because C doesn't allow easy method chaining, and instead leans towards nested function calls.

This is an attempt to create a flexible and easy version for C.


In the future there may be a shared library or a python extension based on ColrC, but for now I'm finishing out the basic features and testing.