Is it safe to use getchar() and putchar()
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I've been told that I should use fgets and sscanf instead of scanf and I'm just wondering if there are any problems associated with getchar() and putchar() that are similar to the problems with scanf.
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asked Nov 10 at 22:52
HoneyBunchers
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up vote
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I've been told that I should use fgets and sscanf instead of scanf and I'm just wondering if there are any problems associated with getchar() and putchar() that are similar to the problems with scanf.
c
asked Nov 10 at 22:52
HoneyBunchers
133
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I've been told that I should use fgets and sscanf instead of scanf and I'm just wondering if there are any problems associated with getchar() and putchar() that are similar to the problems with scanf.
c
asked Nov 10 at 22:52
HoneyBunchers
133
I've been told that I should use fgets and sscanf instead of scanf and I'm just wondering if there are any problems associated with getchar() and putchar() that are similar to the problems with scanf.
c
c
asked Nov 10 at 22:52
HoneyBunchers
133
asked Nov 10 at 22:52
HoneyBunchers
133
asked Nov 10 at 22:52
HoneyBunchers
133
asked Nov 10 at 22:52
HoneyBunchers
133
asked Nov 10 at 22:52
HoneyBunchers
133
133
add a comment |
add a comment |
2 Answers
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no since getchar and putchar (unlike gets, scanf, fgets) use char types, not char *, so there's no risk of buffer overflow since there's no buffer (there is a buffer since I/O is buffered, but you don't control its size and it's properly managed by the C library)
Be careful when using them in a loop not to recreate security issues in your own code, the ones that you wanted to avoid.
If your goal is to read a string using getchar, you'll have to create a loop to store characters. If you aren't careful, you could end up with the same kind of buffer overflow issues. The problem has just moved somewhere else in your code.
answered Nov 10 at 22:58
Jean-François Fabre
99.7k953109
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The main problem with scanf is that it's pattern language doesn't always allow enough control, particularly if you want to restrict input to a line-oriented format. A secondary problem, which can be overcome by specifying size limits, is that by default string fields are of unlimited size and can therefore overflow their destination buffers.
getchar does not suffer from either of those issues,, for reasons which I hope are obvious.
answered Nov 10 at 23:01
rici
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2 Answers
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active
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2 Answers
2
active
oldest
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up vote
0
down vote
accepted
no since getchar and putchar (unlike gets, scanf, fgets) use char types, not char *, so there's no risk of buffer overflow since there's no buffer (there is a buffer since I/O is buffered, but you don't control its size and it's properly managed by the C library)
Be careful when using them in a loop not to recreate security issues in your own code, the ones that you wanted to avoid.
If your goal is to read a string using getchar, you'll have to create a loop to store characters. If you aren't careful, you could end up with the same kind of buffer overflow issues. The problem has just moved somewhere else in your code.
answered Nov 10 at 22:58
Jean-François Fabre
99.7k953109
add a comment |
up vote
0
down vote
accepted
no since getchar and putchar (unlike gets, scanf, fgets) use char types, not char *, so there's no risk of buffer overflow since there's no buffer (there is a buffer since I/O is buffered, but you don't control its size and it's properly managed by the C library)
Be careful when using them in a loop not to recreate security issues in your own code, the ones that you wanted to avoid.
If your goal is to read a string using getchar, you'll have to create a loop to store characters. If you aren't careful, you could end up with the same kind of buffer overflow issues. The problem has just moved somewhere else in your code.
answered Nov 10 at 22:58
Jean-François Fabre
99.7k953109
add a comment |
up vote
0
down vote
accepted
up vote
0
down vote
accepted
no since getchar and putchar (unlike gets, scanf, fgets) use char types, not char *, so there's no risk of buffer overflow since there's no buffer (there is a buffer since I/O is buffered, but you don't control its size and it's properly managed by the C library)
Be careful when using them in a loop not to recreate security issues in your own code, the ones that you wanted to avoid.
If your goal is to read a string using getchar, you'll have to create a loop to store characters. If you aren't careful, you could end up with the same kind of buffer overflow issues. The problem has just moved somewhere else in your code.
answered Nov 10 at 22:58
Jean-François Fabre
99.7k953109
no since getchar and putchar (unlike gets, scanf, fgets) use char types, not char *, so there's no risk of buffer overflow since there's no buffer (there is a buffer since I/O is buffered, but you don't control its size and it's properly managed by the C library)
Be careful when using them in a loop not to recreate security issues in your own code, the ones that you wanted to avoid.
If your goal is to read a string using getchar, you'll have to create a loop to store characters. If you aren't careful, you could end up with the same kind of buffer overflow issues. The problem has just moved somewhere else in your code.
answered Nov 10 at 22:58
Jean-François Fabre
99.7k953109
answered Nov 10 at 22:58
Jean-François Fabre
99.7k953109
answered Nov 10 at 22:58
Jean-François Fabre
99.7k953109
answered Nov 10 at 22:58
Jean-François Fabre
99.7k953109
99.7k953109
add a comment |
add a comment |
up vote
1
down vote
The main problem with scanf is that it's pattern language doesn't always allow enough control, particularly if you want to restrict input to a line-oriented format. A secondary problem, which can be overcome by specifying size limits, is that by default string fields are of unlimited size and can therefore overflow their destination buffers.
getchar does not suffer from either of those issues,, for reasons which I hope are obvious.
answered Nov 10 at 23:01
rici
151k19131194
add a comment |
up vote
1
down vote
The main problem with scanf is that it's pattern language doesn't always allow enough control, particularly if you want to restrict input to a line-oriented format. A secondary problem, which can be overcome by specifying size limits, is that by default string fields are of unlimited size and can therefore overflow their destination buffers.
getchar does not suffer from either of those issues,, for reasons which I hope are obvious.
answered Nov 10 at 23:01
rici
151k19131194
add a comment |
up vote
1
down vote
up vote
1
down vote
The main problem with scanf is that it's pattern language doesn't always allow enough control, particularly if you want to restrict input to a line-oriented format. A secondary problem, which can be overcome by specifying size limits, is that by default string fields are of unlimited size and can therefore overflow their destination buffers.
getchar does not suffer from either of those issues,, for reasons which I hope are obvious.
answered Nov 10 at 23:01
rici
151k19131194
The main problem with scanf is that it's pattern language doesn't always allow enough control, particularly if you want to restrict input to a line-oriented format. A secondary problem, which can be overcome by specifying size limits, is that by default string fields are of unlimited size and can therefore overflow their destination buffers.
getchar does not suffer from either of those issues,, for reasons which I hope are obvious.
answered Nov 10 at 23:01
rici
151k19131194
answered Nov 10 at 23:01
rici
151k19131194
answered Nov 10 at 23:01
rici
151k19131194
answered Nov 10 at 23:01
rici
151k19131194
151k19131194
add a comment |
add a comment |
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