nativeUtils.txt

https://www.geeksforgeeks.org/c-plus-plus/

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Makefile tutorail
https://makefiletutorial.com/

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counting clock cycles
https://stackoverflow.com/questions/5121442/how-to-count-cycles

https://www.geeksforgeeks.org/chrono-in-c/

https://www.tutorialspoint.com/c_standard_library/c_function_clock.htm
The C library function clock_t clock(void) returns the number of clock ticks (processor time, as the linux man)
elapsed since the program was launched. To get the number of seconds used by the
CPU, you will need to divide by CLOCKS_PER_SEC.

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Optimization flags
https://www.rapidtables.com/code/linux/gcc/gcc-o.html

https://refspecs.linuxbase.org/elf/gabi4+/ch4.intro.html

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Overloading the << operator
https://learn.microsoft.com/en-us/cpp/standard-library/overloading-the-output-operator-for-your-own-classes?view=msvc-170

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difference between include with quotes and brackets...
https://www.geeksforgeeks.org/difference-between-include-and-include-in-c-c-with-examples

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Default constructors
https://en.cppreference.com/w/cpp/language/default_constructor

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Criando bibliotecas dinâmicas
https://iq.opengenus.org/create-shared-library-in-cpp/

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Lembrar que gcc/g++ não são apenas compilers!! São linkers tbem!!!!
Quando criamos um executável, gcc/g++ está compilando E linkando...
E tbem podemos fazer apenas um ou outro (compilação e/ou linking)

 "For example, the -c option says not to run the linker.  Then the
 output consists of object files output"

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gbscluster-5.0.0-5000.x86_64.rpm
readelf -d  /path/to/library.so | grep SONAME

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Name mangling -> C++ compilers do that (changing the name of a
function to allow function overloading). But C language doesn't have function overloading.
So, to enable C++ to use C code, they are all declared in an 'extern "C"' block

https://www.geeksforgeeks.org/extern-c-in-c/

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Testes unitários
https://google.github.io/googletest/primer.html

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int myNumbers[5] = {10, 20, 30, 40, 50};
int getArrayLength = sizeof(myNumbers) / sizeof(int);
cout << getArrayLength;

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https://www.geeksforgeeks.org/multithreading-in-cpp/

detach call to leave thread on its own (do not wait for it to finish)
https://stackoverflow.com/questions/21619682/sigabrt-signal-received-when-creating-a-stdthread-c11

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copy array
https://stackoverflow.com/questions/12328301/cleanest-way-to-copy-a-constant-size-array-in-c11

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https://stackoverflow.com/questions/2692383/convert-struct-into-bytes
https://stackoverflow.com/questions/3318410/pragma-pack-effect


https://stackoverflow.com/questions/2301007/determine-word-size-of-my-processor

https://stackoverflow.com/questions/19995440/c-cast-byte-array-to-struct
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https://engineering.linkedin.com/blog/2021/taming-memory-fragmentation-in-venice-with-jemalloc

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https://stackoverflow.com/questions/669438/how-to-get-memory-usage-at-runtime-using-c

#include <iostream>
#include <fstream>

using namespace std;

int main() {

    int tSize = 0, resident = 0, share = 0;
    ifstream buffer("/proc/self/statm");
    buffer >> tSize >> resident >> share;
    buffer.close();

    long page_size_kb = sysconf(_SC_PAGE_SIZE) / 1024; // in case x86-64 is configured to use 2MB pages
    double rss = resident * page_size_kb;
    cout << "RSS - " << rss << " kB\n";

    double shared_mem = share * page_size_kb;
    cout << "Shared Memory - " << shared_mem << " kB\n";

    cout << "Private Memory - " << rss - shared_mem << "kB\n";
    return 0;
}

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https://stackoverflow.com/questions/1246260/why-dont-c-header-files-increase-the-binarys-size

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Most Efficient ways to read a file into a std::string
https://insanecoding.blogspot.com/2011/11/how-to-read-in-file-in-c.html

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https://www.prepbytes.com/blog/linked-list/merge-two-unsorted-linked-lists-to-get-a-sorted-list/
https://stackoverflow.com/questions/1449703/how-to-append-a-listt-object-to-another

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https://unix.stackexchange.com/questions/468766/understanding-output-of-lscpu

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https://stackoverflow.com/questions/11041299/python-h-no-such-file-or-directory

./configure --prefix=/opt/python3.7 --enable-shared
make
make test
sudo make install

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TODO
  lib para contagem de ciclos de clock - ok
  projeto com CMake linkando libs dinamicas - ok (exemplo de linkagem da nossa lib de contagem)
  testes unitarios com gtest
  projeto com OATPP
    -> loggers debug/info
  estudar JNA
  Adress Sanitizer (ASAN)


"/home/pedro.bastos/videoFacesResultTest/video_examples/teste/video_0.20_0.35.mp4"

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std::multiset
https://stackoverflow.com/questions/15582504/is-there-a-sorted-container-in-the-stl
https://en.cppreference.com/w/cpp/container/multiset
https://stackoverflow.com/questions/9167745/in-stdmultiset-is-there-a-function-or-algorithm-to-erase-just-one-sample-unic

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nunca dar throw sem tratamento dentro de uma thread separada kkk
https://stackoverflow.com/questions/45783126/exception-not-caught-if-raised-after-spawning-stdthread

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if statements with Regex - shell script
https://www.baeldung.com/linux/regex-inside-if-clause

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reading file into byte buffer

long MatcherFacade::readTemplatesFromFile2(const std::string& tptPath, char **buffer) {
  FILE *fileptr;
  //  char *buffer;
  long filelen;

  fileptr = fopen(tptPath.c_str(), "rb");  // Open the file in binary mode
  fseek(fileptr, 0, SEEK_END);          // Jump to the end of the file
  filelen = ftell(fileptr);             // Get the current byte offset in the file
  rewind(fileptr);                      // Jump back to the beginning of the file

  *buffer = (char *)malloc(filelen * sizeof(char)); // Enough memory for the file
  fread(*buffer, filelen, 1, fileptr); // Read in the entire file
  fclose(fileptr); // Close the file
  return filelen;
}

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lembrar que cada máquina tem seu clock e que isso interfere bastante quando falamos testes de performance
principalmente com gigantescas quantidades de registros.... (1e6 ++)

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GCC é mais antigo, então não tem tantas otimizações quanto compiladores mais recentes tal como o LLVM.
  -> LLVM compila código C++???
  -> https://clang.llvm.org/
  -> https://stackoverflow.com/questions/9148488/how-do-i-compile-c-with-clang

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set(CMAKE_EXPORT_COMPILE_COMMANDS true) -> para imprimir flags de debug em todos os objetos se colocado no CMkaeList da raiz
set(CMAKE_CXX_FLAGS_DEBUG "-fPIC -O3 -DNDEBUG -s") -> colocar no CMakeList da raiz para afetar todos os objetos
set(CMAKE_CXX_FLAGS_RELEASE "-fPIC -O3 -DNDEBUG -s") -> colocar no CMakeList da raiz para afetar todos os objetos

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https://www.linuxfoundation.org/blog/blog/classic-sysadmin-understanding-linux-file-permissions

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mutex IPC (interprocess comunication)

https://stackoverflow.com/questions/42628949/using-pthread-mutex-shared-between-processes-correctly
https://pubs.opengroup.org/onlinepubs/007904875/functions/shm_open.html
https://stackoverflow.com/questions/36629713/shm-unlink-from-the-shell

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o que consegui fazer dar certo!!
https://stackoverflow.com/questions/12439099/interprocess-reader-writer-lock-with-boost

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Para printar um u_int8 como um HEX
//  printf("%02X ", reference[0]);
//  printf("%02X ", reference[1]);

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boomm...
pq às vezes é melhor deixar alguns headers na implementação?? no .cpp...
  -> pq justamente ficarão apenas na implementação
  -> se alguém for usar uma lib que implementei e der um include em um .h meu não irá pegar os .h adicionados na implementação....

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Valgrind tool suite (massif and etc...)
https://valgrind.org/info/tools.html

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Para ver todas as conexões TCP abertas via websocket (both ways)
  netstat -tuplna | grep 8080

Para contagem de threads de um processo
  ps -o thcount 189310

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gerando bytes aleatórios
https://stackoverflow.com/questions/25298585/efficiently-generating-random-bytes-of-data-in-c11-14

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-> Olha aí a explicação do pq o calloc = 0 quando otimizados não funcionaram.....
  -> https://stackoverflow.com/questions/73555398/can-i-prevent-the-gcc-optimizer-from-delaying-memory-allocation

A simple and ugly way to ensure that the memory buffer gets its hardware backing would be to find the smallest possible
page size on your architecture (which would be 4 kiB on a x86_64, for example, so 1024 of those integers (well, in most
cases)) and then touch each (possible) page of that memory beforehand, as in: for (size_t i = 0; i < 0x80000000; i += 1024) buffer[i] = 1;


That may well be the case. I believe the point was that 0 might get optimized away by the kernel by swapping the page for a shared
read-only zero page (perhaps later on), not that it must happen.