Espaços nominais
Variantes
Acções

std::clock

Da cppreference.com
< cpp‎ | chrono‎ | c

 
 
Biblioteca de utilitários
Digite apoio (basic types, RTTI, type traits)
Gerenciamento de memória dinâmica
De tratamento de erros
Utilidades do programa
Variadic funções
Data e hora
Objetos de função
initializer_list(C++11)
bitset
hash(C++11)
Os operadores relacionais
Original:
Relational operators
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
rel_ops::operator!=
rel_ops::operator>
rel_ops::operator<=
rel_ops::operator>=
Pares e tuplas
Original:
Pairs and tuples
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
pair
tuple(C++11)
piecewise_construct_t(C++11)
piecewise_construct(C++11)
Troque, avançar e avançar
Original:
Swap, forward and move
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
swap
forward(C++11)
move(C++11)
move_if_noexcept(C++11)
declval(C++11)
 
 
C estilo de utilitários de data e hora
Funções
Original:
Functions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Manipulação do tempo
Original:
Time manipulation
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
difftime
time
clock
Conversões de formato
Original:
Format conversions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
asctime
ctime
strftime
wcsftime
gmtime
localtime
mktime
Constantes
Original:
Constants
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
CLOCKS_PER_SEC
Tipos
Original:
Types
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
tm
time_t
clock_t
 
Defined in header <ctime>
std::clock_t clock();
Retorna a hora aproximada do processador usado no processo, desde o início de uma era definida pela implementação relacionada com a execução do programa. Para converter o valor resultado para segundo dividir por CLOCKS_PER_SEC. Uma vez que o início da era std::clock não tem que coincidir com o início do programa, apenas a diferença entre dois valores devolvidos por chamadas para diferentes std::clock é significativo. Se a CPU é compartilhada por outros processos, o tempo std::clock pode avançar mais lento do que relógio de parede. Se o processo atual é de vários segmentos e mais de um núcleo de execução está disponível, o tempo std::clock pode avançar mais rápido do relógio de parede.
Original:
Returns the approximate processor time used by the process since the beginning of an implementation-defined era related to the program's execution. To convert result value to seconds divide it by CLOCKS_PER_SEC. Because the beginning of the std::clock era does not have to coincide with the start of the program, only the difference between two values returned by different calls to std::clock is meaningful. If the CPU is shared by other processes, std::clock time may advance slower than wall clock. If the current process is multithreaded and more than one execution core is available, std::clock time may advance faster than wall clock.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Índice

[editar] Parâmetros

(Nenhum)
Original:
(none)
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[editar] Valor de retorno

Tempo de processador usado pelo programa até agora ou (clock_t)(-1) se que a informação não está disponível.
Original:
Processor time used by the program so far or (clock_t)(-1) if that information is unavailable.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[editar] Notas

Em POSIX sistemas compatíveis, clock_gettime com relógio ID CLOCK_PROCESS_CPUTIME_ID oferece melhor resolução.
Original:
On POSIX-compatible systems, clock_gettime with clock id CLOCK_PROCESS_CPUTIME_ID offers better resolution.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
O valor retornado por clock() pode envolver em torno de algumas implementações. Por exemplo, em uma máquina com 32-bit std::clock_t, envolve depois 2,147 segundo ou 36 minutos.
Original:
The value returned by clock() may wrap around on some implementations. For example, on a machine with 32-bit std::clock_t, it wraps after 2147 seconds or 36 minutes.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
clock() não é necessário para ser thread-safe.
Original:
clock() is not required to be thread-safe.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[editar] Exemplo

Este exemplo demonstra a diferença entre o relógio () tempo e em tempo real
Original:
This example demonstrates the difference between clock() time and real time
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

#include <iostream>
#include <chrono>
#include <ctime>
#include <thread>
 
// the function f() does some time-consuming work
void f()
{
    volatile double d;
    for(int n=0; n<10000; ++n)
       for(int m=0; m<10000; ++m)
           d += d*n*m;
}
 
int main()
{
    std::clock_t c_start = std::clock();
    auto t_start = std::chrono::high_resolution_clock::now();
    std::thread t1(f); 
    std::thread t2(f); // f() is called on two threads
    t1.join();
    t2.join();
    std::clock_t c_end = std::clock();
    auto t_end = std::chrono::high_resolution_clock::now();
 
    std::cout << "CPU time used: "
              << 1000.0 * (c_end-c_start) / CLOCKS_PER_SEC
              << " ms\n";
    std::cout << "Wall clock time passed: "
              << std::chrono::duration_cast<std::chrono::milliseconds>(t_end - t_start).count()
              << " ms\n";
}

Output:

CPU time used: 1520 ms
Wall clock time passed: 769 ms

[editar] Veja também

converte um objeto time_t a uma representação textual
Original:
converts a time_t object to a textual representation
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

(função) [edit]
retorna o tempo atual do sistema como o tempo desde época
Original:
returns the current time of the system as time since epoch
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

(função) [edit]
C documentation for clock