std::basic_ios::fail

 

C++

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I / O操縱

C-風格的I / O

緩衝區 Original: Buffers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

basic_streambuf

basic_filebuf

basic_stringbuf

strstreambuf （過時了）

流 Original: Streams The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

抽象 Original: Abstractions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

ios_base

basic_ios

basic_istream

basic_ostream

basic_iostream

文件I / O Original: File I/O The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

basic_ifstream

basic_ofstream

basic_fstream

字元串I / O Original: String I/O The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

basic_istringstream

basic_ostringstream

basic_stringstream

陣列的I / O Original: Array I/O The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

istrstream （過時了）

ostrstream （過時了）

strstream （過時了）

類型 Original: Types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

streamoff

streamsize

fpos

Error類的介面 Original: Error category interface The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

iostream_category （C++11）

io_errc （C++11）

 

std::basic_ios

成員函數 Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

basic_ios::basic_ios

basic_ios::~basic_ios

國家職能 Original: State functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

basic_ios::good

basic_ios::eof

basic_ios::fail

basic_ios::bad

basic_ios::operator!

basic_ios::operator bool

basic_ios::rdstate

basic_ios::setstate

basic_ios::clear

格式化 Original: Formatting The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

basic_ios::copyfmt

basic_ios::fill

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basic_ios::exceptions

basic_ios::imbue

basic_ios::rdbuf

basic_ios::tie

basic_ios::narrow

basic_ios::widen

受保護的成員函數 Original: Protected member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

basic_ios::init

basic_ios::move

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basic_ios::set_rdbuf

 

bool fail() const;

返回true如果發生了錯誤相關的流。具體而言，回報true如果badbit或failbit設置rdstate().

Original:

Returns true if an error has occurred on the associated stream. Specifically, returns true if badbit or failbit is set in rdstate().

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參數

（無）

Original:

(none)

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返回值

true如果已發生錯誤，false否則.

Original:

true if an error has occurred, false otherwise.

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為例

#include <iostream>
#include <fstream>
#include <cstdlib>
int main()
{
    std::ifstream file("test.txt");
    if(!file)  // operator! is used here
    {  
        std::cout << "File opening failed\n";
        return EXIT_FAILURE;
    }
 
    // typical C++ I/O loop uses the return value of the I/O function
    // as the loop controlling condition, operator bool() is used here
    for(int n; file >> n; ) {
       std::cout << n << ' ';
    }
    std::cout << '\n';
 
    if (file.bad())
        std::cout << "I/O error while reading\n";
    else if (file.eof())
        std::cout << "End of file reached successfully\n";
    else if (file.fail())
        std::cout << "Non-integer data encountered\n";
}

另請參閱

ios_base::iostate flags			basic_ios accessors
eofbit	failbit	badbit	good()	fail()	bad()	eof()	operator bool()	operator!()
false	false	false	true	false	false	false	true	false
false	false	true	false	true	true	false	false	true
false	true	false	false	true	false	false	false	true
false	true	true	false	true	true	false	false	true
true	false	false	false	false	false	true	true	false
true	false	true	false	true	true	true	false	true
true	true	false	false	true	false	true	false	true
true	true	true	false	true	true	true	false	true

ferror	檢查文件錯誤 Original: checks for a file error The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函數）