C++ Filehandling: Difference between ios:app and ios:ate?
What's the difference between ios::ate and ios:app when writing to a file.
In my view, ios::app gives you the ability to move around in the file, whereas with ios::ate it can only read/write at the end of the file. Is this correct?
c++ file fstream c++-standard-library
edited Jul 19 '16 at 12:57
iammilind
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asked Apr 28 '12 at 1:12
Adam_G
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add a comment |
What's the difference between ios::ate and ios:app when writing to a file.
In my view, ios::app gives you the ability to move around in the file, whereas with ios::ate it can only read/write at the end of the file. Is this correct?
c++ file fstream c++-standard-library
edited Jul 19 '16 at 12:57
iammilind
44.4k19124249
asked Apr 28 '12 at 1:12
Adam_G
2,193114593
add a comment |
What's the difference between ios::ate and ios:app when writing to a file.
In my view, ios::app gives you the ability to move around in the file, whereas with ios::ate it can only read/write at the end of the file. Is this correct?
c++ file fstream c++-standard-library
edited Jul 19 '16 at 12:57
iammilind
44.4k19124249
asked Apr 28 '12 at 1:12
Adam_G
2,193114593
What's the difference between ios::ate and ios:app when writing to a file.
In my view, ios::app gives you the ability to move around in the file, whereas with ios::ate it can only read/write at the end of the file. Is this correct?
c++ file fstream c++-standard-library
c++ file fstream c++-standard-library
edited Jul 19 '16 at 12:57
iammilind
44.4k19124249
asked Apr 28 '12 at 1:12
Adam_G
2,193114593
edited Jul 19 '16 at 12:57
iammilind
44.4k19124249
asked Apr 28 '12 at 1:12
Adam_G
2,193114593
edited Jul 19 '16 at 12:57
iammilind
44.4k19124249
edited Jul 19 '16 at 12:57
iammilind
44.4k19124249
edited Jul 19 '16 at 12:57
iammilind
44.4k19124249
44.4k19124249
asked Apr 28 '12 at 1:12
Adam_G
2,193114593
asked Apr 28 '12 at 1:12
Adam_G
2,193114593
asked Apr 28 '12 at 1:12
Adam_G
2,193114593
2,193114593
add a comment |
add a comment |
5 Answers
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active
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It’s the other way around. When ios::ate is set, the initial position will be the end of the file, but you are free to seek thereafter. When ios::app is set, all output operations are performed at the end of the file. Since all writes are implicitly preceded by seeks, there is no way to write elsewhere.
answered Apr 28 '12 at 1:17
Jon Purdy
37.7k666125
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They are specified as follows (in 27.5.3.1.4 of C++11):
appseek to end before each write
ateopen and seek to end immediately after opening
With ios::app the write position in the file is "sticky" -- all writes are at the end, no matter where you seek.
answered Apr 28 '12 at 1:16
Steve Jessop
232k26365624
add a comment |
It is pretty good documented here.
ios::ate "sets the stream's position indicator to the end of the stream on opening."
ios:app "set the stream's position indicator to the end of the stream before each output operation."
This means the difference that ios::ate puts your position to the end of the file when you open it. ios::app instead puts it at the end of the file every time you flush your stream. If for example you two programs that write to the same log file ios:ate will override anything that was added to the file by the other program since your program opened it. ios:app will instead jump to the end of file each time your programm adds a log entry.
answered Apr 28 '12 at 1:21
Haatschii
4,60983982
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App:
we cannot move the pointer.It will be only at end
Ate:
we can move the record pointer to any other place
answered Sep 23 '13 at 10:14
naveen
8711
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The ios::ate option is for input and output operations andios::app allows us to add data to the end of file.
edited May 17 '18 at 6:08
Jonathan Rys
1,146520
answered May 17 '18 at 2:03
toijam sonalika devi
1
Can you provide a link to documentation?
– harvpan
May 17 '18 at 2:27
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protected by Hovercraft Full Of Eels Nov 11 '18 at 22:07
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5 Answers
5
active
oldest
votes
5 Answers
5
active
oldest
votes
active
oldest
votes
active
oldest
votes
It’s the other way around. When ios::ate is set, the initial position will be the end of the file, but you are free to seek thereafter. When ios::app is set, all output operations are performed at the end of the file. Since all writes are implicitly preceded by seeks, there is no way to write elsewhere.
answered Apr 28 '12 at 1:17
Jon Purdy
37.7k666125
add a comment |
It’s the other way around. When ios::ate is set, the initial position will be the end of the file, but you are free to seek thereafter. When ios::app is set, all output operations are performed at the end of the file. Since all writes are implicitly preceded by seeks, there is no way to write elsewhere.
answered Apr 28 '12 at 1:17
Jon Purdy
37.7k666125
add a comment |
It’s the other way around. When ios::ate is set, the initial position will be the end of the file, but you are free to seek thereafter. When ios::app is set, all output operations are performed at the end of the file. Since all writes are implicitly preceded by seeks, there is no way to write elsewhere.
answered Apr 28 '12 at 1:17
Jon Purdy
37.7k666125
It’s the other way around. When ios::ate is set, the initial position will be the end of the file, but you are free to seek thereafter. When ios::app is set, all output operations are performed at the end of the file. Since all writes are implicitly preceded by seeks, there is no way to write elsewhere.
answered Apr 28 '12 at 1:17
Jon Purdy
37.7k666125
answered Apr 28 '12 at 1:17
Jon Purdy
37.7k666125
answered Apr 28 '12 at 1:17
Jon Purdy
37.7k666125
answered Apr 28 '12 at 1:17
Jon Purdy
37.7k666125
37.7k666125
add a comment |
add a comment |
They are specified as follows (in 27.5.3.1.4 of C++11):
appseek to end before each write
ateopen and seek to end immediately after opening
With ios::app the write position in the file is "sticky" -- all writes are at the end, no matter where you seek.
answered Apr 28 '12 at 1:16
Steve Jessop
232k26365624
add a comment |
They are specified as follows (in 27.5.3.1.4 of C++11):
appseek to end before each write
ateopen and seek to end immediately after opening
With ios::app the write position in the file is "sticky" -- all writes are at the end, no matter where you seek.
answered Apr 28 '12 at 1:16
Steve Jessop
232k26365624
add a comment |
They are specified as follows (in 27.5.3.1.4 of C++11):
appseek to end before each write
ateopen and seek to end immediately after opening
With ios::app the write position in the file is "sticky" -- all writes are at the end, no matter where you seek.
answered Apr 28 '12 at 1:16
Steve Jessop
232k26365624
They are specified as follows (in 27.5.3.1.4 of C++11):
appseek to end before each write
ateopen and seek to end immediately after opening
With ios::app the write position in the file is "sticky" -- all writes are at the end, no matter where you seek.
answered Apr 28 '12 at 1:16
Steve Jessop
232k26365624
answered Apr 28 '12 at 1:16
Steve Jessop
232k26365624
answered Apr 28 '12 at 1:16
Steve Jessop
232k26365624
answered Apr 28 '12 at 1:16
Steve Jessop
232k26365624
232k26365624
add a comment |
add a comment |
It is pretty good documented here.
ios::ate "sets the stream's position indicator to the end of the stream on opening."
ios:app "set the stream's position indicator to the end of the stream before each output operation."
This means the difference that ios::ate puts your position to the end of the file when you open it. ios::app instead puts it at the end of the file every time you flush your stream. If for example you two programs that write to the same log file ios:ate will override anything that was added to the file by the other program since your program opened it. ios:app will instead jump to the end of file each time your programm adds a log entry.
answered Apr 28 '12 at 1:21
Haatschii
4,60983982
add a comment |
It is pretty good documented here.
ios::ate "sets the stream's position indicator to the end of the stream on opening."
ios:app "set the stream's position indicator to the end of the stream before each output operation."
This means the difference that ios::ate puts your position to the end of the file when you open it. ios::app instead puts it at the end of the file every time you flush your stream. If for example you two programs that write to the same log file ios:ate will override anything that was added to the file by the other program since your program opened it. ios:app will instead jump to the end of file each time your programm adds a log entry.
answered Apr 28 '12 at 1:21
Haatschii
4,60983982
add a comment |
It is pretty good documented here.
ios::ate "sets the stream's position indicator to the end of the stream on opening."
ios:app "set the stream's position indicator to the end of the stream before each output operation."
This means the difference that ios::ate puts your position to the end of the file when you open it. ios::app instead puts it at the end of the file every time you flush your stream. If for example you two programs that write to the same log file ios:ate will override anything that was added to the file by the other program since your program opened it. ios:app will instead jump to the end of file each time your programm adds a log entry.
answered Apr 28 '12 at 1:21
Haatschii
4,60983982
It is pretty good documented here.
ios::ate "sets the stream's position indicator to the end of the stream on opening."
ios:app "set the stream's position indicator to the end of the stream before each output operation."
This means the difference that ios::ate puts your position to the end of the file when you open it. ios::app instead puts it at the end of the file every time you flush your stream. If for example you two programs that write to the same log file ios:ate will override anything that was added to the file by the other program since your program opened it. ios:app will instead jump to the end of file each time your programm adds a log entry.
answered Apr 28 '12 at 1:21
Haatschii
4,60983982
edited Mar 13 '16 at 13:41
answered Apr 28 '12 at 1:21
Haatschii
4,60983982
answered Apr 28 '12 at 1:21
Haatschii
4,60983982
answered Apr 28 '12 at 1:21
Haatschii
4,60983982
4,60983982
add a comment |
add a comment |
App:
we cannot move the pointer.It will be only at end
Ate:
we can move the record pointer to any other place
answered Sep 23 '13 at 10:14
naveen
8711
add a comment |
App:
we cannot move the pointer.It will be only at end
Ate:
we can move the record pointer to any other place
answered Sep 23 '13 at 10:14
naveen
8711
add a comment |
App:
we cannot move the pointer.It will be only at end
Ate:
we can move the record pointer to any other place
answered Sep 23 '13 at 10:14
naveen
8711
App:
we cannot move the pointer.It will be only at end
Ate:
we can move the record pointer to any other place
answered Sep 23 '13 at 10:14
naveen
8711
answered Sep 23 '13 at 10:14
naveen
8711
answered Sep 23 '13 at 10:14
naveen
8711
answered Sep 23 '13 at 10:14
naveen
8711
8711
add a comment |
add a comment |
The ios::ate option is for input and output operations andios::app allows us to add data to the end of file.
edited May 17 '18 at 6:08
Jonathan Rys
1,146520
answered May 17 '18 at 2:03
toijam sonalika devi
1
Can you provide a link to documentation?
– harvpan
May 17 '18 at 2:27
add a comment |
The ios::ate option is for input and output operations andios::app allows us to add data to the end of file.
edited May 17 '18 at 6:08
Jonathan Rys
1,146520
answered May 17 '18 at 2:03
toijam sonalika devi
1
Can you provide a link to documentation?
– harvpan
May 17 '18 at 2:27
add a comment |
The ios::ate option is for input and output operations andios::app allows us to add data to the end of file.
edited May 17 '18 at 6:08
Jonathan Rys
1,146520
answered May 17 '18 at 2:03
toijam sonalika devi
1
The ios::ate option is for input and output operations andios::app allows us to add data to the end of file.
edited May 17 '18 at 6:08
Jonathan Rys
1,146520
answered May 17 '18 at 2:03
toijam sonalika devi
1
edited May 17 '18 at 6:08
Jonathan Rys
1,146520
edited May 17 '18 at 6:08
Jonathan Rys
1,146520
edited May 17 '18 at 6:08
Jonathan Rys
1,146520
1,146520
answered May 17 '18 at 2:03
toijam sonalika devi
1
answered May 17 '18 at 2:03
toijam sonalika devi
1
answered May 17 '18 at 2:03
toijam sonalika devi
1
1
Can you provide a link to documentation?
– harvpan
May 17 '18 at 2:27
add a comment |
Can you provide a link to documentation?
– harvpan
May 17 '18 at 2:27
Can you provide a link to documentation?
– harvpan
May 17 '18 at 2:27
Can you provide a link to documentation?
– harvpan
May 17 '18 at 2:27
add a comment |
protected by Hovercraft Full Of Eels Nov 11 '18 at 22:07
Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).
Would you like to answer one of these unanswered questions instead?
