What's the difference between opening a file with ios::binary or ios::out or both?
17
I'm trying to figure out the difference between opening a file like:
fstream *fileName*("FILE.dat",ios::binary);
or
fstream *fileName*("FILE.dat",ios::out);
or
fstream *fileName*("FILE.dat",ios::binary | ios::out);
I found that all of these forms are identical: in all cases, the same output on the file is produced using either *fileName*<< or *fileName*.write().
c++ fstream
edited Dec 2 '15 at 0:58
Jamal
60662229
asked Feb 8 '10 at 23:08
Alan_AI
72631329
add a comment |
17
I'm trying to figure out the difference between opening a file like:
fstream *fileName*("FILE.dat",ios::binary);
or
fstream *fileName*("FILE.dat",ios::out);
or
fstream *fileName*("FILE.dat",ios::binary | ios::out);
I found that all of these forms are identical: in all cases, the same output on the file is produced using either *fileName*<< or *fileName*.write().
c++ fstream
edited Dec 2 '15 at 0:58
Jamal
60662229
asked Feb 8 '10 at 23:08
Alan_AI
72631329
add a comment |
17
17
17
3
I'm trying to figure out the difference between opening a file like:
fstream *fileName*("FILE.dat",ios::binary);
or
fstream *fileName*("FILE.dat",ios::out);
or
fstream *fileName*("FILE.dat",ios::binary | ios::out);
I found that all of these forms are identical: in all cases, the same output on the file is produced using either *fileName*<< or *fileName*.write().
c++ fstream
edited Dec 2 '15 at 0:58
Jamal
60662229
asked Feb 8 '10 at 23:08
Alan_AI
72631329
I'm trying to figure out the difference between opening a file like:
fstream *fileName*("FILE.dat",ios::binary);
or
fstream *fileName*("FILE.dat",ios::out);
or
fstream *fileName*("FILE.dat",ios::binary | ios::out);
I found that all of these forms are identical: in all cases, the same output on the file is produced using either *fileName*<< or *fileName*.write().
c++ fstream
c++ fstream
edited Dec 2 '15 at 0:58
Jamal
60662229
asked Feb 8 '10 at 23:08
Alan_AI
72631329
edited Dec 2 '15 at 0:58
Jamal
60662229
asked Feb 8 '10 at 23:08
Alan_AI
72631329
edited Dec 2 '15 at 0:58
Jamal
60662229
edited Dec 2 '15 at 0:58
Jamal
60662229
edited Dec 2 '15 at 0:58
Jamal
60662229
60662229
asked Feb 8 '10 at 23:08
Alan_AI
72631329
asked Feb 8 '10 at 23:08
Alan_AI
72631329
asked Feb 8 '10 at 23:08
Alan_AI
72631329
72631329
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
23
ios::out opens the file for writing.
ios::binary makes sure the data is read or written without translating new line characters to and from rn on the fly. In other words, exactly what you give the stream is exactly what's written.
answered Feb 8 '10 at 23:12
Nick Bedford
3,7442432
and what does it mean to use both?
– Alan_AI
Feb 8 '10 at 23:36
Well, you'd be writing to a file without translating any characters.
– Nick Bedford
Feb 9 '10 at 0:04
2
So if I don't mark an ifstream as binary, and read, say 10 doubles from it, and Windows finds a random 'n' in the data, then the stream get expanded from10*sizeof(double)to10*sizeof(double) +1as aris inserted, and overwrites then end of my double buffer?
– user14717
Apr 10 '15 at 13:46
1
is it good practice to use ios::binary all the time?
– FluorescentGreen5
Oct 13 '16 at 4:53
add a comment |
5
Opening a file with ios::binary controls how newline characters are handled. On Windows, they are expanded to CRLF pairs. That's it - it has no effect on how things like operator<< work.
but what are CLRF pairs?
– Alan_AI
Feb 8 '10 at 23:30
2
CLRF stands for carriage-return, line feed. These are the two bytes used to specify a new line in Windows text encoding. It's mostly redundant because on a computer, you really only need a new-line character.
– Nick Bedford
Feb 9 '10 at 0:05
3
Long time ago, in the days of Teletypes and typewriters, output machines had carriages that moved left to write as characters were printed. One command,Carriage Return, moved the carriage back to the left. Another command,Linefeed, advanced the paper to the next line. These two commands could be executed independently so that the paper advanced mid-line (usingLinefeed) or rewriting the current line (usingCarriage Return). As a pair, they cause the printing to start at the left margin of the next line.
– Thomas Matthews
Feb 9 '10 at 0:26
6
Unix people, being impatient typists, decided that the computer should handle bothCarriage ReturnsandLinefeeds, improving productivity by typing less characters. This new command was calledNewline. On some output systems you could see the carriage move left and the paper advance for eachNewline, including blank lines. The C language decided to make peace and let the OS provide translations (withoutios::binary) or provide no translations (withios::binary). Theios::outdetermines data direction (out from the computer).
– Thomas Matthews
Feb 9 '10 at 0:32
thank u mr. Thomas so can u give me one difference between using ios::binary and ios::out | ios::binary for opening a file r nt they identical?
– Alan_AI
Feb 9 '10 at 1:22
add a comment |
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2 Answers
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2 Answers
2
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active
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oldest
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23
ios::out opens the file for writing.
ios::binary makes sure the data is read or written without translating new line characters to and from rn on the fly. In other words, exactly what you give the stream is exactly what's written.
answered Feb 8 '10 at 23:12
Nick Bedford
3,7442432
and what does it mean to use both?
– Alan_AI
Feb 8 '10 at 23:36
Well, you'd be writing to a file without translating any characters.
– Nick Bedford
Feb 9 '10 at 0:04
2
So if I don't mark an ifstream as binary, and read, say 10 doubles from it, and Windows finds a random 'n' in the data, then the stream get expanded from10*sizeof(double)to10*sizeof(double) +1as aris inserted, and overwrites then end of my double buffer?
– user14717
Apr 10 '15 at 13:46
1
is it good practice to use ios::binary all the time?
– FluorescentGreen5
Oct 13 '16 at 4:53
add a comment |
23
ios::out opens the file for writing.
ios::binary makes sure the data is read or written without translating new line characters to and from rn on the fly. In other words, exactly what you give the stream is exactly what's written.
answered Feb 8 '10 at 23:12
Nick Bedford
3,7442432
and what does it mean to use both?
– Alan_AI
Feb 8 '10 at 23:36
Well, you'd be writing to a file without translating any characters.
– Nick Bedford
Feb 9 '10 at 0:04
2
So if I don't mark an ifstream as binary, and read, say 10 doubles from it, and Windows finds a random 'n' in the data, then the stream get expanded from10*sizeof(double)to10*sizeof(double) +1as aris inserted, and overwrites then end of my double buffer?
– user14717
Apr 10 '15 at 13:46
1
is it good practice to use ios::binary all the time?
– FluorescentGreen5
Oct 13 '16 at 4:53
add a comment |
23
23
23
ios::out opens the file for writing.
ios::binary makes sure the data is read or written without translating new line characters to and from rn on the fly. In other words, exactly what you give the stream is exactly what's written.
answered Feb 8 '10 at 23:12
Nick Bedford
3,7442432
ios::out opens the file for writing.
ios::binary makes sure the data is read or written without translating new line characters to and from rn on the fly. In other words, exactly what you give the stream is exactly what's written.
answered Feb 8 '10 at 23:12
Nick Bedford
3,7442432
answered Feb 8 '10 at 23:12
Nick Bedford
3,7442432
answered Feb 8 '10 at 23:12
Nick Bedford
3,7442432
answered Feb 8 '10 at 23:12
Nick Bedford
3,7442432
3,7442432
and what does it mean to use both?
– Alan_AI
Feb 8 '10 at 23:36
Well, you'd be writing to a file without translating any characters.
– Nick Bedford
Feb 9 '10 at 0:04
2
So if I don't mark an ifstream as binary, and read, say 10 doubles from it, and Windows finds a random 'n' in the data, then the stream get expanded from10*sizeof(double)to10*sizeof(double) +1as aris inserted, and overwrites then end of my double buffer?
– user14717
Apr 10 '15 at 13:46
1
is it good practice to use ios::binary all the time?
– FluorescentGreen5
Oct 13 '16 at 4:53
add a comment |
and what does it mean to use both?
– Alan_AI
Feb 8 '10 at 23:36
Well, you'd be writing to a file without translating any characters.
– Nick Bedford
Feb 9 '10 at 0:04
2
So if I don't mark an ifstream as binary, and read, say 10 doubles from it, and Windows finds a random 'n' in the data, then the stream get expanded from10*sizeof(double)to10*sizeof(double) +1as aris inserted, and overwrites then end of my double buffer?
– user14717
Apr 10 '15 at 13:46
1
is it good practice to use ios::binary all the time?
– FluorescentGreen5
Oct 13 '16 at 4:53
and what does it mean to use both?
– Alan_AI
Feb 8 '10 at 23:36
and what does it mean to use both?
– Alan_AI
Feb 8 '10 at 23:36
Well, you'd be writing to a file without translating any characters.
– Nick Bedford
Feb 9 '10 at 0:04
Well, you'd be writing to a file without translating any characters.
– Nick Bedford
Feb 9 '10 at 0:04
2
2
So if I don't mark an ifstream as binary, and read, say 10 doubles from it, and Windows finds a random 'n' in the data, then the stream get expanded from
10*sizeof(double) to 10*sizeof(double) +1 as a r is inserted, and overwrites then end of my double buffer?– user14717
Apr 10 '15 at 13:46
So if I don't mark an ifstream as binary, and read, say 10 doubles from it, and Windows finds a random 'n' in the data, then the stream get expanded from
10*sizeof(double) to 10*sizeof(double) +1 as a r is inserted, and overwrites then end of my double buffer?– user14717
Apr 10 '15 at 13:46
1
1
is it good practice to use ios::binary all the time?
– FluorescentGreen5
Oct 13 '16 at 4:53
is it good practice to use ios::binary all the time?
– FluorescentGreen5
Oct 13 '16 at 4:53
add a comment |
5
Opening a file with ios::binary controls how newline characters are handled. On Windows, they are expanded to CRLF pairs. That's it - it has no effect on how things like operator<< work.
but what are CLRF pairs?
– Alan_AI
Feb 8 '10 at 23:30
2
CLRF stands for carriage-return, line feed. These are the two bytes used to specify a new line in Windows text encoding. It's mostly redundant because on a computer, you really only need a new-line character.
– Nick Bedford
Feb 9 '10 at 0:05
3
Long time ago, in the days of Teletypes and typewriters, output machines had carriages that moved left to write as characters were printed. One command,Carriage Return, moved the carriage back to the left. Another command,Linefeed, advanced the paper to the next line. These two commands could be executed independently so that the paper advanced mid-line (usingLinefeed) or rewriting the current line (usingCarriage Return). As a pair, they cause the printing to start at the left margin of the next line.
– Thomas Matthews
Feb 9 '10 at 0:26
6
Unix people, being impatient typists, decided that the computer should handle bothCarriage ReturnsandLinefeeds, improving productivity by typing less characters. This new command was calledNewline. On some output systems you could see the carriage move left and the paper advance for eachNewline, including blank lines. The C language decided to make peace and let the OS provide translations (withoutios::binary) or provide no translations (withios::binary). Theios::outdetermines data direction (out from the computer).
– Thomas Matthews
Feb 9 '10 at 0:32
thank u mr. Thomas so can u give me one difference between using ios::binary and ios::out | ios::binary for opening a file r nt they identical?
– Alan_AI
Feb 9 '10 at 1:22
add a comment |
5
Opening a file with ios::binary controls how newline characters are handled. On Windows, they are expanded to CRLF pairs. That's it - it has no effect on how things like operator<< work.
but what are CLRF pairs?
– Alan_AI
Feb 8 '10 at 23:30
2
CLRF stands for carriage-return, line feed. These are the two bytes used to specify a new line in Windows text encoding. It's mostly redundant because on a computer, you really only need a new-line character.
– Nick Bedford
Feb 9 '10 at 0:05
3
Long time ago, in the days of Teletypes and typewriters, output machines had carriages that moved left to write as characters were printed. One command,Carriage Return, moved the carriage back to the left. Another command,Linefeed, advanced the paper to the next line. These two commands could be executed independently so that the paper advanced mid-line (usingLinefeed) or rewriting the current line (usingCarriage Return). As a pair, they cause the printing to start at the left margin of the next line.
– Thomas Matthews
Feb 9 '10 at 0:26
6
Unix people, being impatient typists, decided that the computer should handle bothCarriage ReturnsandLinefeeds, improving productivity by typing less characters. This new command was calledNewline. On some output systems you could see the carriage move left and the paper advance for eachNewline, including blank lines. The C language decided to make peace and let the OS provide translations (withoutios::binary) or provide no translations (withios::binary). Theios::outdetermines data direction (out from the computer).
– Thomas Matthews
Feb 9 '10 at 0:32
thank u mr. Thomas so can u give me one difference between using ios::binary and ios::out | ios::binary for opening a file r nt they identical?
– Alan_AI
Feb 9 '10 at 1:22
add a comment |
5
5
5
Opening a file with ios::binary controls how newline characters are handled. On Windows, they are expanded to CRLF pairs. That's it - it has no effect on how things like operator<< work.
Opening a file with ios::binary controls how newline characters are handled. On Windows, they are expanded to CRLF pairs. That's it - it has no effect on how things like operator<< work.
answered Feb 8 '10 at 23:14
anon
but what are CLRF pairs?
– Alan_AI
Feb 8 '10 at 23:30
2
CLRF stands for carriage-return, line feed. These are the two bytes used to specify a new line in Windows text encoding. It's mostly redundant because on a computer, you really only need a new-line character.
– Nick Bedford
Feb 9 '10 at 0:05
3
Long time ago, in the days of Teletypes and typewriters, output machines had carriages that moved left to write as characters were printed. One command,Carriage Return, moved the carriage back to the left. Another command,Linefeed, advanced the paper to the next line. These two commands could be executed independently so that the paper advanced mid-line (usingLinefeed) or rewriting the current line (usingCarriage Return). As a pair, they cause the printing to start at the left margin of the next line.
– Thomas Matthews
Feb 9 '10 at 0:26
6
Unix people, being impatient typists, decided that the computer should handle bothCarriage ReturnsandLinefeeds, improving productivity by typing less characters. This new command was calledNewline. On some output systems you could see the carriage move left and the paper advance for eachNewline, including blank lines. The C language decided to make peace and let the OS provide translations (withoutios::binary) or provide no translations (withios::binary). Theios::outdetermines data direction (out from the computer).
– Thomas Matthews
Feb 9 '10 at 0:32
thank u mr. Thomas so can u give me one difference between using ios::binary and ios::out | ios::binary for opening a file r nt they identical?
– Alan_AI
Feb 9 '10 at 1:22
add a comment |
but what are CLRF pairs?
– Alan_AI
Feb 8 '10 at 23:30
2
CLRF stands for carriage-return, line feed. These are the two bytes used to specify a new line in Windows text encoding. It's mostly redundant because on a computer, you really only need a new-line character.
– Nick Bedford
Feb 9 '10 at 0:05
3
Long time ago, in the days of Teletypes and typewriters, output machines had carriages that moved left to write as characters were printed. One command,Carriage Return, moved the carriage back to the left. Another command,Linefeed, advanced the paper to the next line. These two commands could be executed independently so that the paper advanced mid-line (usingLinefeed) or rewriting the current line (usingCarriage Return). As a pair, they cause the printing to start at the left margin of the next line.
– Thomas Matthews
Feb 9 '10 at 0:26
6
Unix people, being impatient typists, decided that the computer should handle bothCarriage ReturnsandLinefeeds, improving productivity by typing less characters. This new command was calledNewline. On some output systems you could see the carriage move left and the paper advance for eachNewline, including blank lines. The C language decided to make peace and let the OS provide translations (withoutios::binary) or provide no translations (withios::binary). Theios::outdetermines data direction (out from the computer).
– Thomas Matthews
Feb 9 '10 at 0:32
thank u mr. Thomas so can u give me one difference between using ios::binary and ios::out | ios::binary for opening a file r nt they identical?
– Alan_AI
Feb 9 '10 at 1:22
but what are CLRF pairs?
– Alan_AI
Feb 8 '10 at 23:30
but what are CLRF pairs?
– Alan_AI
Feb 8 '10 at 23:30
2
2
CLRF stands for carriage-return, line feed. These are the two bytes used to specify a new line in Windows text encoding. It's mostly redundant because on a computer, you really only need a new-line character.
– Nick Bedford
Feb 9 '10 at 0:05
CLRF stands for carriage-return, line feed. These are the two bytes used to specify a new line in Windows text encoding. It's mostly redundant because on a computer, you really only need a new-line character.
– Nick Bedford
Feb 9 '10 at 0:05
3
3
Long time ago, in the days of Teletypes and typewriters, output machines had carriages that moved left to write as characters were printed. One command,
Carriage Return, moved the carriage back to the left. Another command, Linefeed, advanced the paper to the next line. These two commands could be executed independently so that the paper advanced mid-line (using Linefeed) or rewriting the current line (using Carriage Return). As a pair, they cause the printing to start at the left margin of the next line.– Thomas Matthews
Feb 9 '10 at 0:26
Long time ago, in the days of Teletypes and typewriters, output machines had carriages that moved left to write as characters were printed. One command,
Carriage Return, moved the carriage back to the left. Another command, Linefeed, advanced the paper to the next line. These two commands could be executed independently so that the paper advanced mid-line (using Linefeed) or rewriting the current line (using Carriage Return). As a pair, they cause the printing to start at the left margin of the next line.– Thomas Matthews
Feb 9 '10 at 0:26
6
6
Unix people, being impatient typists, decided that the computer should handle both
Carriage Returns and Linefeeds, improving productivity by typing less characters. This new command was called Newline. On some output systems you could see the carriage move left and the paper advance for each Newline, including blank lines. The C language decided to make peace and let the OS provide translations (without ios::binary) or provide no translations (with ios::binary). The ios::out determines data direction (out from the computer).– Thomas Matthews
Feb 9 '10 at 0:32
Unix people, being impatient typists, decided that the computer should handle both
Carriage Returns and Linefeeds, improving productivity by typing less characters. This new command was called Newline. On some output systems you could see the carriage move left and the paper advance for each Newline, including blank lines. The C language decided to make peace and let the OS provide translations (without ios::binary) or provide no translations (with ios::binary). The ios::out determines data direction (out from the computer).– Thomas Matthews
Feb 9 '10 at 0:32
thank u mr. Thomas so can u give me one difference between using ios::binary and ios::out | ios::binary for opening a file r nt they identical?
– Alan_AI
Feb 9 '10 at 1:22
thank u mr. Thomas so can u give me one difference between using ios::binary and ios::out | ios::binary for opening a file r nt they identical?
– Alan_AI
Feb 9 '10 at 1:22
add a comment |
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