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CTL is a fast compiling, type safe, header only, template-like library for ISO C99/C11.


CTL aims to improve ISO C99/C11 developer productivity by implementing the following STL containers in ISO C99/C11:

deq.h = std::deque
lst.h = std::list
pqu.h = std::priority_queue
que.h = std::queue
set.h = std::set
stk.h = std::stack
str.h = std::string
ust.h = std::unordered_set
vec.h = std::vector


Configure a CTL container with a built-in or typedef type T.

#include <stdio.h>

#define P
#define T int
#include <vec.h>

int compare(int* a, int* b) { return *b < *a; }

int main(void)
    vec_int a = vec_int_init();
    vec_int_push_back(&a, 9);
    vec_int_push_back(&a, 1);
    vec_int_push_back(&a, 8);
    vec_int_push_back(&a, 3);
    vec_int_push_back(&a, 4);
    vec_int_sort(&a, compare);
    foreach(vec_int, &a, it)
        printf("%d\n", *it.ref);

Definition P states type T is Plain Old Data (POD).

To compile, include the ctl directory:

gcc main.c -I ctl

For a much more thorough getting started guide, see the wiki:

Memory Ownership

Types with memory ownership require definition P be omitted, and require function declarations for the C++ equivalent of the destructor and copy constructor, prior to the inclusion of the container:

typedef struct { ... } type;
void type_free(type*);
type type_copy(type*);
#define T type
#include <vec.h>

Forgetting a declaration will print a human-readable error message:

tests/test_c11.c:11:11: error: type_free undeclared (first use in this function)
   11 | #define T type


CTL performance is presented in solid colors, and STL in dotted colors, for template type T as type int for all measurements.

Omitted from these performance measurements are que.h, stk.h, and str.h, as their performance characteristics can be inferred from deq.h, and vec.h, respectively.

Note, CTL strings do not support short strings.

Running Tests

To run all functional tests, run:


To compile examples, run:

make examples

To generate performance graphs, run:

# Graphing requires python3 and the Plotly family of libraries via pip.
pip install plotly
pip install psutil
pip install kaleido

To do all of the above in one step, run:


For maintaining CTL, a container templated to type int can be outputted to stdout by running make on the container name, eg:

make deq
make lst
make pqu
make que
make set
make stk
make str
make ust
make vec


STL std::map will not be implemented in CTL because maps only provide slight syntactic improvements over sets.

STL variants of multi-sets and multi-maps will not be implemented because similar behaviour can be implemented as an amalgamation of a set and lst.

Base Implementation Details

vec.h: realloc
str.h: vec.h
deq.h: realloc (paged)
que.h: deq.h
stk.h: deq.h
pqu.h: vec.h
lst.h: doubly linked list
set.h: red black tree
ust.h: hashed forward linked lists

                    vec  str  deq  lst  set  pqu  que  stk  ust
empty               x    x    x    x    x    x    x    x    x
each                x    x    x    x    x                   x
equal               x    x    x    x    x    x    x    x    x
swap                x    x    x    x    x    x    x    x    x
bucket                                                      x
bucket_size                                                 x
load_factor                                                 x
rehash                                                      x
insert              x    x    x    x    x                   x
init                x    x    x    x    x    x    x    x    x
free                x    x    x    x    x    x    x    x    x
step                x    x    x    x    x                   x
range               x    x    x    x    x                   x
find                x    x    x    x    x                   x
count                    x              x                   x
lower_bound                             x                   
upper_bound                             x                   
erase               x    x    x    x    x                   x
copy                x    x    x    x    x                   x
begin               x    x    x    x    x                   x
end                 x    x    x    x    x                   x
intersection                            x                   
union                                   x                   
difference                              x                   
symmetric_difference                    x                   
top                                          x         x
push                                         x    x    x
pop                                          x    x    x
at                  x    x    x
front               x    x    x    x              x
back                x    x    x    x              x
set                 x    x    x
pop_back            x    x    x    x
pop_front                     x    x
clear               x    x    x    x    x
reserve             x    x
push_back           x    x    x    x
push_front                    x    x
transfer                           x
disconnect                         x
connect                            x
resize              x    x    x    x
assign              x    x    x    x
reverse                            x
shrink_to_fit       x    x
data                x    x
erase_node                              x
sort                x    x    x    x
remove_if           x    x    x    x    x
splice                             x
merge                              x
unique                             x
append                   x
insert_str               x
replace                  x              x
c_str                    x
find                     x
rfind                    x
find_first_of            x
find_last_of             x
find_first_not_of        x
find_last_not_of         x
substr                   x
compare                  x
key_compare              x


Thank you for the Plotly code, and thank you for the general review and manual testing.

Thank you smlckz for the foreach cleanup.

Thank you for the addition of set lower_bound and upper_bound.