std::cerr, std::wcerr
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| Definido no cabeçalho <iostream>
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| extern std::ostream cerr; |
(1) | |
| extern std::wostream wcerr; |
(2) | |
Os objectos globais std::cerr e std::wcerr saída de controle de fluxo de um tampão de aplicação (tipo definido derivado de std::streambuf e std::wstreambuf, respectivamente), associado com o padrão de fluxo de saída de erro C stderr.
Original:
The global objects std::cerr and std::wcerr control output to a stream buffer of implementation-defined type (derived from std::streambuf and std::wstreambuf, respectively), associated with the standard C error output stream stderr.
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Esses objetos são garantidos para ser construído antes de o primeiro construtor de um objeto estático é chamado e eles são garantidos para sobreviver à última destruidor de um objeto estático, de modo que é sempre possível escrever para std::cerr no código do usuário.
Original:
These objects are guaranteed to be constructed before the first constructor of a static object is called and they are guaranteed to outlive the last destructor of a static object, so that it is always possible to write to std::cerr in user code.
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A menos que sync_with_stdio(false) foi emitido, ele é seguro para acessar simultaneamente esses objetos de vários segmentos, tanto para saída formatada e não formatado.
Original:
Unless sync_with_stdio(false) has been issued, it is safe to concurrently access these objects from multiple threads for both formatted and unformatted output.
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Uma vez inicializado, std::cerr.flags() & unitbuf != 0 significado (o mesmo para
wcerr) que qualquer saída enviada para esses objetos de fluxo é imediatamente liberado para o OS (via destruidor de std::basic_ostream::sentry).Original:
Once initialized, std::cerr.flags() & unitbuf != 0 (same for
wcerr) meaning that any output sent to these stream objects is immediately flushed to the OS (via std::basic_ostream::sentry's destructor).The text has been machine-translated via Google Translate.
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Além disso, std::cerr.tie() retornos &std::cout (mesmo para
wcerr e wcout), o que significa que qualquer operação de saída em std::cerr primeiro executa std::cout.flush() (via construtor de std::basic_ostream::sentry) (desde C++11)Original:
In addition, std::cerr.tie() returns &std::cout (same for
wcerr and wcout), meaning that any output operation on std::cerr first executes std::cout.flush() (via std::basic_ostream::sentry's constructor) (desde C++11)The text has been machine-translated via Google Translate.
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[editar] Exemplo
saída para stderr via ondas de cerr fora a saída dependendo cout, enquanto a produção de stderr via obstrução não
Original:
output to stderr via cerr flushes out the pending output on cout, while output to stderr via clog does not
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#include <thread> #include <iostream> #include <chrono> void f() { std::cout << "Output from thread..."; std::this_thread::sleep_for(std::chrono::seconds(2)); std::cout << "...thread calls flush()" << std::endl; } int main() { std::thread t1(f); std::this_thread::sleep_for(std::chrono::seconds(1)); std::clog << "This output from main is not tie()'d to cout\n"; std::cerr << "This output is tie()'d to cout\n"; t1.join(); }
Saída:
This output from main is not tie()'d to cout Output from thread...This output is tie()'d to cout ...thread calls flush()
[editar] Veja também
| inicializa objetos de fluxo padrão Original: initializes standard stream objects The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (of std::ios_base public class membro)
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| escreve para o padrão stderr
(objeto global) fluxo de erro C Original: writes to the standard C error stream stderr (objeto global) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. | |
| grava o padrão de fluxo de saída stdout
(objeto global) C Original: writes to the standard C output stream stdout (objeto global) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. | |
