std::unitbuf, std::nounitbuf
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<metanoindex/>
<tbody> </tbody>| Déclaré dans l'en-tête <ios>
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std::ios_base& unitbuf( std::ios_base& str ); |
(1) | |
std::ios_base& nounitbuf( std::ios_base& str ); |
(2) | |
Active ou désactive rinçage automatique du courant de sortie après une opération de sortie. N'a aucun effet sur entrée .
Original:
Enables or disables automatic flushing of the output stream after any output operation. Has no effect on input.
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1)
permet le drapeau
unitbuf dans le flux str comme si en appelant str.setf(std::ios_base::unitbuf)Original:
enables the
unitbuf flag in the stream str as if by calling str.setf(std::ios_base::unitbuf)The text has been machine-translated via Google Translate.
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2)
désactive le drapeau
unitbuf dans le flux str comme si en appelant str.unsetf(std::ios_base::unitbuf)Original:
disables the
unitbuf flag in the stream str as if by calling str.unsetf(std::ios_base::unitbuf)The text has been machine-translated via Google Translate.
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Il s'agit d'un manipulateur d'E / S, il peut être appelé avec une expression telle que pour tout
out << std::unitbuf out de std::basic_ostream type ou d'une expression telle que pour tout in >> std::unitbuf in de std::basic_istream type .Original:
This is an I/O manipulator, it may be called with an expression such as
out << std::unitbuf for any out of type std::basic_ostream or with an expression such as in >> std::unitbuf for any in of type std::basic_istream.The text has been machine-translated via Google Translate.
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Notes
Le rinçage est effectué dans le destructeur de l'objet std::basic_ostream::sentry, qui appelle
str.rdbuf()->pubsync() si str.flags() & std::ios_base::unitbuf == true .Original:
Flushing is performed in the destructor of the std::basic_ostream::sentry object, which calls
str.rdbuf()->pubsync() if str.flags() & std::ios_base::unitbuf == true.The text has been machine-translated via Google Translate.
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Les objets de sortie standard std::cerr et std::wcerr ont leur bit
unitbuf fixé par défaut .Original:
The standard output objects std::cerr and std::wcerr have their
unitbuf bit set by default.The text has been machine-translated via Google Translate.
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Paramètres
| str | - | référence aux flux d'entrée / sortie
Original: reference to I/O stream The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
Retourne la valeur
str (référence au flux après la manipulation)Original:
str (reference to the stream after manipulation)The text has been machine-translated via Google Translate.
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Exemple
Sans std :: unitbuf ou d'une autre couleur explicite, le résultat est le même, mais ne semble pas en temps réel .
Original:
Without std::unitbuf or another explicit flush, the output is the same, but does not appear in real time.
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#include <iostream>
#include <chrono>
template<typename Diff>
void log_progress(Diff d)
{
std::cout << "..("
<< std::chrono::duration_cast<std::chrono::milliseconds>(d).count()
<< " ms)..";
}
int main()
{
volatile int sink=0;
std::cout << std::unitbuf; // enable automatic flushing
auto t1 = std::chrono::high_resolution_clock::now();
for(int j=0; j<5; ++j)
{
for(int n=0; n<10000; ++n)
for(int m=0; m<20000; ++m)
sink += m*n; // do some work
auto now = std::chrono::high_resolution_clock::now();
log_progress(now - t1);
}
std::cout << '\n';
}
Résultat :
..(450 ms)....(902 ms)....(1352 ms)....(1802 ms)....(2252 ms)..
Voir aussi
vide le flux de sortie Original: flushes the output stream The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction générique) | |
sorties '\n' et vide le flux de sortieOriginal: outputs '\n' and flushes the output streamThe text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction générique) |