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Is there posibility (any method) to check count of bytes read by function presented below:
istream& read (char* s, streamsize n);
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Other ways to read a std::istreamTo read a line of input, try the getline() function. For this, you need #include <string> in addition to #include <iostream> . To read a single char: use the get() method. To read a large block of characters, either use get() with a char[] as the argument, or use read() .
Opening a File The object ifs can be instantiated from the ifstream class using the first syntax with the statement: ifstream ifs; In this case, a file object ifs has been created but the file is not yet opened. To open the file for reading, the open member function of the ifstream class has to be used.
Implementations return the number of bytes read. The implementation will block until at least one byte of data can be read, in the event that no data is available. Read returns 0 only when there is no more data in the stream and no more is expected (such as a closed socket or end of file).
Use the CanRead property to determine whether the current instance supports reading. Use the ReadAsync method to read asynchronously from the current stream. Implementations of this method read a maximum of count bytes from the current stream and store them in buffer beginning at offset.
You can find out by calling gcount () on a stream immediately after you read. ifs.read (buf, sizeof buf); std::streamsize bytes = ifs.gcount (); If gcount () did not read the exact requested, is the fstream object still in a valid state to continue and continue the read? Show activity on this post.
The number of successfully extracted characters can be queried using gcount () . failure if an error occurred (the error state flag is not goodbit) and exceptions () is set to throw for that state. If an internal operation throws an exception, it is caught and badbit is set.
std::streamsize gcount() const;
Returns the number of characters extracted by the last unformatted input operation.
gcount
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