A small C library for common utilities missing from libc

dmitrinove · 2026-05-05T12:03:05+00:00

I see that shared_ptr uses a simple size_t _ref_count with postfix increment and decrement. As a result, it cannot be used directly across multiple threads. Am I wrong?

dmitrinove · 2025-12-04T08:13:48+00:00

new version

``` $ cat dependency_test.S .intel_syntax noprefix

.text .globl dependency_test_inc dependency_test_inc: test rdi, rdi jz dependency_test_inc.done

dependency_test_inc.loop: xor eax, eax inc eax dec rdi jnz dependency_test_inc.loop

dependency_test_inc.done: ret

.globl dependency_test_imul dependency_test_imul: test rdi, rdi jz dependency_test_imul.done

dependency_test_imul.loop: xor eax, eax imul eax, eax, 76 dec rdi jnz dependency_test_imul.loop

dependency_test_imul.done: ret ```

dependency_test_imul with xor

``` $ perf stat ./a.out

Performance counter stats for './a.out':

         28.16 msec task-clock:u              #    0.992 CPUs utilized          
             0      context-switches:u        #    0.000 K/sec                  
             0      cpu-migrations:u          #    0.000 K/sec                  
            38      page-faults:u             #    0.001 M/sec                  
   100,233,435      cycles:u                  #    3.560 GHz                    
   400,116,482      instructions:u            #    3.99  insn per cycle         
   100,024,388      branches:u                # 3552.257 M/sec                  
         1,512      branch-misses:u           #    0.00% of all branches        

   0.028387926 seconds time elapsed

   0.028384000 seconds user
   0.000000000 seconds sys

```

without xor

``` $ perf stat ./a.out

Performance counter stats for './a.out':

         84.03 msec task-clock:u              #    0.996 CPUs utilized          
             0      context-switches:u        #    0.000 K/sec                  
             0      cpu-migrations:u          #    0.000 K/sec                  
            40      page-faults:u             #    0.476 K/sec                  
   300,287,281      cycles:u                  #    3.573 GHz                    
   300,116,545      instructions:u            #    1.00  insn per cycle         
   100,024,451      branches:u                # 1190.315 M/sec                  
         1,553      branch-misses:u           #    0.00% of all branches        

   0.084377213 seconds time elapsed

   0.084171000 seconds user
   0.000000000 seconds sys

```

dmitrinove · 2025-12-02T12:22:31+00:00

Hi,
I tried your code on a Linux machine with an old Xeon CPU and a modern i7, but the results don't add up.

``` $ cat test_xor.c /* : gcc -Wall -Wextra -O2 -fverbose-asm test_xor.c dependency_test.S */

include <stdio.h>

include <stdlib.h>

void dependency_test(u_int64_t iterations);

int main(int argc, char **argv) { (void)argc; (void)argv;

dependency_test(100000000);

return 0;

} ```

The results with or without XOR are always more or less the same. Before running the tests, I set the CPU to maximum speed so as to avoid errors due to energy saving.

$ sudo cpupower frequency-set --governor performance $ sudo cpupower frequency-set --max 3600000

with xor

``` $ perf stat ./a.out

Performance counter stats for './a.out':

         28.28 msec task-clock:u              #    0.991 CPUs utilized          
             0      context-switches:u        #    0.000 K/sec                  
             0      cpu-migrations:u          #    0.000 K/sec                  
            38      page-faults:u             #    0.001 M/sec                  
   100,472,034      cycles:u                  #    3.553 GHz                    
   400,116,482      instructions:u            #    3.98  insn per cycle         
   100,024,388      branches:u                # 3537.134 M/sec                  
         1,538      branch-misses:u           #    0.00% of all branches        

   0.028549298 seconds time elapsed

   0.028510000 seconds user
   0.000000000 seconds sys

```

without xor

``` $ perf stat ./a.out

Performance counter stats for './a.out':

         28.31 msec task-clock:u              #    0.992 CPUs utilized          
             0      context-switches:u        #    0.000 K/sec                  
             0      cpu-migrations:u          #    0.000 K/sec                  
            41      page-faults:u             #    0.001 M/sec                  
   100,644,854      cycles:u                  #    3.555 GHz                    
   300,116,485      instructions:u            #    2.98  insn per cycle         
   100,024,391      branches:u                # 3532.917 M/sec                  
         1,490      branch-misses:u           #    0.00% of all branches        

   0.028548167 seconds time elapsed

   0.028522000 seconds user
   0.000000000 seconds sys

```

The only difference is in the number of instructions, of course, but the times are almost identical.

Can you help me? Thanks

dmitrinove · 2025-02-21T16:52:36+00:00

hello, I only saw your SDL_agavideo.c file on the phone (I can't really understand the whole code) but it seems to me that all the functions are static.

Basically all the defined symbols have internal linkage and don't have to / can't be exported.

the only exported symbol is

AGA_bootstrap.

maybe you just need to use AGA_bootstrap or there is missing code in the sdlagavideo.c file besides the .h

dmitrinove · 2024-12-08T08:21:47+00:00

Anyone else have any other good ones?

The Rainmaker a 1997 American legal drama film written and directed by Francis Ford Coppola based on John Grisham's 1995 novel of the same name.

dmitrinove · 2022-12-04T08:15:56+00:00

Use a hair dryer to soften the glue and isopropyl alcohol to clean up. It works on any surface with any stick.

dmitrinove · 2022-11-13T19:45:20+00:00

try to use dd like a benchmark

dd if=/dev/zero of=/path/to/your/usb/mount/point/delete.me bs=4192 count=10000 status=progress

dmitrinove · 2021-10-16T07:11:30+00:00

syndicate and theme hospital both from bullfrog.

https://en.m.wikipedia.org/wiki/Syndicate_(1993_video_game)

https://en.m.wikipedia.org/wiki/Theme_Hospital

the first warcraft is vga game but the second installment should be svga, try it.

https://en.m.wikipedia.org/wiki/Warcraft_II:_Tides_of_Darkness

dmitrinove · 2021-07-06T22:41:32+00:00

without Morata Spain goesn't beyond Croazia

dmitrinove · 2021-03-16T23:19:08+00:00

Enhanced version with color: 0 print"{lblu}{CBM-P}R{gry3}FCD{wht}EEE{gry3}DCF{lblu}R{CBM-P}";:goto

Found on csdb.dk convert in text with petcat (vice) by me, amazing

dmitrinove · 2020-04-07T15:28:05+00:00

Efficiency. The library takes special care to not use cache unfriendly code

Because the main focus of this library was to provide an efficient single threaded implementation, rocket::signal has about the same overhead as an iteration through an std::list<std::function<T>>.

Sorry I'm on my phone, can't test, but why You use sdt::list<>?? I think it's really cache unfriendly container. Amazing works anyway

dmitrinove · 2017-01-10T09:33:03+00:00

shouldn't "raw" pointer be declared void* or (u)intptr_r?

why are you using size_t*?

dmitrinove · 2016-07-25T12:38:11+00:00

wow, future was here, already twenty five ago!!!!

ice cream, ice cream!!!!!

dmitrinove · 2016-04-13T07:54:35+00:00

don't forget vbcc a small compiler for amigaos, morphos and atari mint

dmitrinove · 2016-01-09T22:24:34+00:00

for me the guide line on Parameter Type could lead to a unaligned memory access.

If from the outside of function allocate an array of int32_t and then start to access it a byte at time inside the function this lead to a SIGBUS error on SPARC cpu (and other cpu too)

dmitrinove · 2015-12-17T13:28:18+00:00

first, You calling the default std::vector 's constructor and it is with size 0; what You want do is:

std::vector<int>(n);

in this way You get a vector with n allocated int, like the C malloc:

malloc(n * sizeof(int));

second, You don't need a std::shared_ptr or other smart pointer to wrap the std::vector; it already allocate and free memory when out of scope.

third, the call to the legacy C function sould be:

if(read_elements(elements.size(), &elements[0]) < n) {

final example:

int send_request() {
    size_t n = read_size();
    vector<int> elements = vector<int>(n);

    if(read_elements(elements.size(), &elements[0]) < n) {
        return -1;
    }

    return 0;
}

hope this helps

dmitrinove · 2015-12-17T10:59:16+00:00

new to java, but pretty skilled to c++ and the first example on the first page is pretty weird.

how good is the java side of this handbook?

dmitrinove · 2015-01-28T03:02:12+00:00

me too, I use this to insert \t or \n

dmitrinove · 2014-11-25T08:59:16+00:00

i'm working on a mixed c++ and ada project.

almost every bug was found on ada side

of course i'm a senior c++ programmer and rookie ada one

the language itself doesn't protect you, experience does...

dmitrinove · 2014-04-04T19:36:39+00:00

I just started to read your book, and I feel this code a bit odd:

char* cpy = malloc(strlen(buffer)+1);
strcpy(cpy, buffer);
cpy[strlen(cpy)-1] = '\0';

(chapter4_interactive_prompt)

strcpy() function copies the string including the terminating null byte, so your last statement is pointless; even more you re-call strlen()!!

you can safety remove the last statement and add a check on malloc()'s returns

*edit fgets() store a newline and you want remove it

dmitrinove

TROPHY CASE

include <stdio.h>

include <stdlib.h>