hello,

is there a c++ equivalent function to the c-function 'sprintf'?

Thank you,

leo

On 2008-10-09 09:33:41 -0400, "A.Leopold" <andreas.leopold@himt.de> said:

>
> is there a c++ equivalent function to the c-function 'sprintf'?
>

Yes. Its name is sprintf.

--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)

ok, I asked, cause my compiler (VS05) is complaining about the use of
sprintf ....

Pete Becker schrieb:
> On 2008-10-09 09:33:41 -0400, "A.Leopold" <andreas.leopold@himt.de> said:
>
>>
>> is there a c++ equivalent function to the c-function 'sprintf'?
>>
>
> Yes. Its name is sprintf.
>

On Oct 9, 3:33pm, "A.Leopold" <andreas.leop...@himt.de> wrote:
> hello,
>
> is there a c++ equivalent function to the c-function 'sprintf'?

Maybe you want to use stringstream.

>
> Thank you,
>
> leo

juanvicfer schrieb:
> On Oct 9, 3:33 pm, "A.Leopold" <andreas.leop...@himt.de> wrote:
>> hello,
>>
>> is there a c++ equivalent function to the c-function 'sprintf'?
>
> Maybe you want to use stringstream.

ok, I will have a look at stringstream

On Oct 9, 9:33 am, "A.Leopold" <andreas.leop...@himt.de> wrote:
> hello,
>
> is there a c++ equivalent function to the c-function 'sprintf'?


You can also check out boost::format, which can be
easier to work with than stringstream:

http://www.boost.org/doc/libs/1_36_0...oc/format.html

Sean

sean_in_raleigh@yahoo.com schrieb:
> On Oct 9, 9:33 am, "A.Leopold" <andreas.leop...@himt.de> wrote:
>> hello,
>>
>> is there a c++ equivalent function to the c-function 'sprintf'?
>
>
> You can also check out boost::format, which can be
> easier to work with than stringstream:
>
> http://www.boost.org/doc/libs/1_36_0...oc/format.html
>
> Sean

thank you, that looks much more convenient!

"A.Leopold" <andreas.leopold@himt.de> writes:

>
> ok, I asked, cause my compiler (VS05) is complaining about the use of
> sprintf ....

I guess it's rather ::sprintf (with extern "C" { / #include <stdio.h> / }).

But if you want some safety, you'd use ::snprintf, and if you don't want to implement
the safety yourself, you could rather use lisp^W std:stringstream.

std:stringstream s; s<<"Hi "<<world<<std::endl;
std::string str =s.str();
const char* cstr=s.c_str();

--
__Pascal Bourguignon__

On Thu, 09 Oct 2008 17:12:56 +0200, A.Leopold wrote:

> sean_in_raleigh@yahoo.com schrieb:
>> On Oct 9, 9:33 am, "A.Leopold" <andreas.leop...@himt.de> wrote:
>>> hello,
>>>
>>> is there a c++ equivalent function to the c-function 'sprintf'?
>>
>>
>> You can also check out boost::format, which can be easier to work with
>> than stringstream:
>>
>> http://www.boost.org/doc/libs/1_36_0...oc/format.html
>>
>> Sean
>
> thank you, that looks much more convenient!

There is also boost::lexical_cast (something like a "cheap and cheerful"
version of stringstream formatting):

http://www.boost.org/doc/libs/1_36_0...xical_cast.htm

--
Lionel B

Pascal J. Bourguignon wrote:

> "A.Leopold" <andreas.leopold@himt.de> writes:
>
> >
> > ok, I asked, cause my compiler (VS05) is complaining about the use
> > of sprintf ....
>
> I guess it's rather ::sprintf (with extern "C" { / #include <stdio.h>
> / }).

What would make you guess something like that?




Brian

"Default User" <defaultuserbr@yahoo.com> writes:

> Pascal J. Bourguignon wrote:
>
>> "A.Leopold" <andreas.leopold@himt.de> writes:
>>
>> >
>> > ok, I asked, cause my compiler (VS05) is complaining about the use
>> > of sprintf ....
>>
>> I guess it's rather ::sprintf (with extern "C" { / #include <stdio.h>
>> / }).
>
> What would make you guess something like that?

First, AFAIK, C functions are in the "root" namespace; to avoid
refering a different object in the current namespace, it's advised (in
various style guides) to qualify C functions.

Then, using a function without declaring it would make a sane compiler
complain, so it's good practice to include some header declaring it
before using it.


--
__Pascal Bourguignon__

Pascal J. Bourguignon wrote:
> "Default User" <defaultuserbr@yahoo.com> writes:
>
>> Pascal J. Bourguignon wrote:
>>
>>> "A.Leopold" <andreas.leopold@himt.de> writes:
>>>
>>>>
>>>> ok, I asked, cause my compiler (VS05) is complaining about the use
>>>> of sprintf ....
>>> I guess it's rather ::sprintf (with extern "C" { / #include <stdio.h>
>>> / }).
>> What would make you guess something like that?
>
> First, AFAIK, C functions are in the "root" namespace; to avoid
> refering a different object in the current namespace, it's advised (in
> various style guides) to qualify C functions.
>
> Then, using a function without declaring it would make a sane compiler
> complain, so it's good practice to include some header declaring it
> before using it.

The is the C++ group here, so the C header <stdio.h> is to be
included using <cstdio> and its content is accessible only within
the 'std' namespace.

Schobi

Pascal J. Bourguignon wrote:

> "Default User" <defaultuserbr@yahoo.com> writes:
>
> > Pascal J. Bourguignon wrote:
> >
> >> "A.Leopold" <andreas.leopold@himt.de> writes:
> >>
> >> >
> >> > ok, I asked, cause my compiler (VS05) is complaining about the
> use >> > of sprintf ....
> >>
> >> I guess it's rather ::sprintf (with extern "C" { / #include
> <stdio.h> >> / }).
> >
> > What would make you guess something like that?
>
> First, AFAIK, C functions are in the "root" namespace;

Not (at least theoretically) if you use the headers like <cstdio>.
However, that's not necessary.

> to avoid
> refering a different object in the current namespace, it's advised (in
> various style guides) to qualify C functions.

I've never seen such a thing.

> Then, using a function without declaring it would make a sane compiler
> complain, so it's good practice to include some header declaring it
> before using it.

That's correct, of course. However, <stdio.h> is a standard C++ header.
Why would you enclose it in extern "C"?




Brian

Pete Becker wrote:
> On 2008-10-09 09:33:41 -0400, "A.Leopold" <andreas.leopold@himt.de> said:
>
>>
>> is there a c++ equivalent function to the c-function 'sprintf'?
>>
>
> Yes. Its name is sprintf.

Assuming that line is preceded by "using std::sprintf;".

On Oct 9, 8:45am, "A.Leopold" <andreas.leop...@himt.de> wrote:
>
> ok, I asked, cause my compiler (VS05) is complaining about the use of
> sprintf ....


Please don't top-post.

If you're getting the MSVC warning about depreciated functions, you
may ignore that, or turn off the warning with the appropriate compiler
option, #pragma or #define. Current versions of MSVC warn about the
use of many traditional functions which have the potential, if used
incorrectly, to lead to buffer overflows. MS has taken a fair bit of
heat for this, especially because they chose to describe the functions
as "depreciated" (which means something specific in terms of the
language standard), instead of something describing the risk. In most
cases they provide a (Microsoft specific) replacement function which
has the potential to be used more easily in a safe way (for example,
the non-standard sprintf_s is offered as a "safer" replacement for
sprintf).

The did it to a number of C++ library functions to. For example,
basic_string::copy is "depreciated" while the non-standard
basic_string::_Copy_s is provided as a "safer" alternative.

http://msdn.microsoft.com/en-us/libr...ys(VS.80).aspx

Jeff Schwab wrote:
> Pete Becker wrote:
>> On 2008-10-09 09:33:41 -0400, "A.Leopold" <andreas.leopold@himt.de> said:
>>
>>>
>>> is there a c++ equivalent function to the c-function 'sprintf'?
>>>
>>
>> Yes. Its name is sprintf.
>
> Assuming that line is preceded by "using std::sprintf;".

That depends on which header you include. From what I've seen, people
still prefer <stdio.h> over <cstdio>.

--
Ian Collins

A.Leopold wrote:


> is there a c++ equivalent function to the c-function 'sprintf'?

Assuming that vnsprintf is C99 or C++0X compliant
that std:string is contiguous (as in C++0X) and
that writing \0 at str[ str.size() ] is harmless,
you could try:

bool strprintf ( std::string & buffer, char const * format, ... ) {
while ( true ) {
buffer.resize( buffer.capacity() );
int old_length = buffer.size();
std::va_list aq;
va_start( aq, format );
int length_needed =
vsnprintf( &buffer[0], old_length + 1, format, aq );
va_end( aq );
if ( length_needed < 0 ) {
return ( false );
}
buffer.resize( length_needed );
if ( length_needed <= old_length ) {
return ( true );
}
}
}

This will do what sprintf() does, except it will use a std::string as the
target and increase it when needed.


Best

Kai-Uwe Bux

Ian Collins wrote:
> Jeff Schwab wrote:
>> Pete Becker wrote:
>>> On 2008-10-09 09:33:41 -0400, "A.Leopold" <andreas.leopold@himt.de> said:
>>>
>>>> is there a c++ equivalent function to the c-function 'sprintf'?
>>>>
>>> Yes. Its name is sprintf.
>> Assuming that line is preceded by "using std::sprintf;".
>
> That depends on which header you include. From what I've seen, people
> still prefer <stdio.h> over <cstdio>.

Where are you seeing this? IME, it's vanishingly rare, and generally a
sign of incompetence.

Jeff Schwab wrote:
> Ian Collins wrote:
>> Jeff Schwab wrote:
>>> Pete Becker wrote:
>>>> On 2008-10-09 09:33:41 -0400, "A.Leopold" <andreas.leopold@himt.de> said:
>>>>
>>>>> is there a c++ equivalent function to the c-function 'sprintf'?
>>>>>
>>>> Yes. Its name is sprintf.
>>> Assuming that line is preceded by "using std::sprintf;".
>> That depends on which header you include. From what I've seen, people
>> still prefer <stdio.h> over <cstdio>.
>
> Where are you seeing this? IME, it's vanishingly rare, and generally a
> sign of incompetence.

I wish it were rare.

Schobi

In article <0494ee48-d50e-4ec3-8099-48c699c3dc2e@m32g2000hsf.googlegroups.com>,
robertwessel2@yahoo.com <robertwessel2@yahoo.com> wrote:
>On Oct 9, 8:45am, "A.Leopold" <andreas.leop...@himt.de> wrote:
>>
>> ok, I asked, cause my compiler (VS05) is complaining about the use of
>> sprintf ....
>
>
>Please don't top-post.
>
>If you're getting the MSVC warning about depreciated functions, you
>may ignore that, or turn off the warning with the appropriate compiler
>option, #pragma or #define. Current versions of MSVC warn about the
>use of many traditional functions which have the potential, if used
>incorrectly, to lead to buffer overflows. MS has taken a fair bit of
>heat for this, especially because they chose to describe the functions
>as "depreciated" (which means something specific in terms of the
>language standard), instead of something describing the risk. In most
>cases they provide a (Microsoft specific) replacement function which
>has the potential to be used more easily in a safe way (for example,
>the non-standard sprintf_s is offered as a "safer" replacement for
>sprintf).
>
>The did it to a number of C++ library functions to. For example,
>basic_string::copy is "depreciated" while the non-standard
>basic_string::_Copy_s is provided as a "safer" alternative.
>
>http://msdn.microsoft.com/en-us/libr...ys(VS.80).aspx



I am nout sure you need to go that far into dodgy non-standard
functions.

sprintf should in almost all places be replaced by snprintf.
snprintf is perfectly standard and I think it would silence the
warning.

Yannick

In article <48ee0ae3$1@news.arcor-ip.de>,
A.Leopold <andreas.leopold@himt.de> wrote:
>
>ok, I asked, cause my compiler (VS05) is complaining about the use of
>sprintf ....


sprintf is a buffer overflow waiting to happen.

Use snprintf instead.

# man sprintf
-------selected text--------
BUGS
Because sprintf() and vsprintf() assume an arbitrarily long string,
callers must be careful not to overflow the actual space; this is
often impossible to assure. Note that the length of the strings
produced is locale-dependent and difficult to predict. Use snprintf()
and vsnprintf() instead (or asprintf() and vasprintf).
----------------------------

Alternatively, learn abount C++ streams but that would require more
significant changes to your code.

Yannick

In message <1223980571.309748@irys.nyx.net>, Yannick Tremblay
<ytrembla@nyx.nyx.net> writes
>In article <48ee0ae3$1@news.arcor-ip.de>,
>A.Leopold <andreas.leopold@himt.de> wrote:
>>
>>ok, I asked, cause my compiler (VS05) is complaining about the use of
>>sprintf ....
>
>
>sprintf is a buffer overflow waiting to happen.
>
>Use snprintf instead.

.... that way you only have an out-by-1 error waiting to happen ;-/

--
Richard Herring

In article <vinvNJK$3H9IFwkq@baesystems.com>,
Richard Herring <richard.herring@baesystems.com> wrote:
>In message <1223980571.309748@irys.nyx.net>, Yannick Tremblay
><ytrembla@nyx.nyx.net> writes
>>In article <48ee0ae3$1@news.arcor-ip.de>,
>>A.Leopold <andreas.leopold@himt.de> wrote:
>>>
>>>ok, I asked, cause my compiler (VS05) is complaining about the use of
>>>sprintf ....
>>
>>
>>sprintf is a buffer overflow waiting to happen.
>>
>>Use snprintf instead.
>
>... that way you only have an out-by-1 error waiting to happen ;-/

I did consider adding a warning of snprintf too since I have often
encountered the out-by-one error. Not that long ago mentionning in
passing to a programmer the he should use streams instead cause they
are less bug prone but he replied that it was alright in that case
cause he was safely using the same definition for his array size
and his snprintf only for a couple of weeks later figuring out that
there was indead a out-by-1 error in his code. The typical excuse of
course is that C++ streams are not efficient (snprintf is faster) even
if there has been no measurement done and that particular piece of
code is not in a critical loop :-(

But despite all of that, sprintf is fundamentally flawed in many
situation because it can be impossible to write safe code with it as
you can't verify that the buffer was big enough. snprintf makes it
possible to write safe code. Even if you need to be careful with the
out-by-1 errors.

Personally, I am lazy. I use string streams :-)


Yannick

In article <0494ee48-d50e-4ec3-8099-48c699c3dc2e@m32g2000hsf.googlegroups.com>,
robertwessel2@yahoo.com <robertwessel2@yahoo.com> wrote:
>
>If you're getting the MSVC warning about depreciated functions, you
>may ignore that, or turn off the warning with the appropriate compiler
>option, #pragma or #define. Current versions of MSVC warn about the
>use of many traditional functions which have the potential, if used
>incorrectly, to lead to buffer overflows. MS has taken a fair bit of
>heat for this, especially because they chose to describe the functions
>as "depreciated" (which means something specific in terms of the
>language standard), instead of something describing the risk. In most
>cases they provide a (Microsoft specific) replacement function which
>has the potential to be used more easily in a safe way (for example,
>the non-standard sprintf_s is offered as a "safer" replacement for
>sprintf).
>
>The did it to a number of C++ library functions to. For example,
>basic_string::copy is "depreciated" while the non-standard
>basic_string::_Copy_s is provided as a "safer" alternative.
>
>http://msdn.microsoft.com/en-us/libr...ys(VS.80).aspx
>

Arrghh!!! I went and glance at this link. what a bunch of idiots:

--------------------------------------
size_type copy(
value_type* _Ptr,
size_type _Count,
size_type _Off = 0
) const;

This method is potentially unsafe, as it relies on the caller to check
that the passed values are correct. Consider using
basic_string::_Copy_s instead.

size_type _Copy_s(
value_type *_Dest,
size_type _Dest_size,
size_type _Count,
size_type _Off = 0
) const;
--------------------------------------------

Hmm, It also relies on the caller to send the correct value in
_Dest_size. If I am too incompetent to send a valid _Count, how do
they expect me to send a valid _Dest_size?

Even worse for read:
-------------------------------------------
basic_istream& read(
char_type *_Str,
streamsize _Count
);

This method is potentially unsafe, as it relies on the caller to check
that the passed values are correct. Consider using
basic_istream::_Read_s instead.

basic_istream& _Read_s(
char_type *_Str,
size_t _Str_size,
streamsize _Count
);
-------------------------------

So this is only ever useful if I am idiot enough to call this method
with _Count > _Str_size.

By all mean, deprecate functions like sprintf that have no way
toindicate a maximum size. However, all they have done is duplicate
an already exisiting safety mechanism. By all mean, it might, just
might catch a couple of errors but mostly poor code will look like:

#define MAX_SIZE 20;
char c[MAX_SIZE];
cin._Read_s(&c[0], MAX_SIZE, MAX_SIZE);

which has the same bug as:

#define MAX_SIZE 20;
char c[MAX_SIZE];
cin.read(&c[0], MAX_SIZE); // or cin.read(c, sizeof(c))

Bunch of ....

Yannick

On Oct 11, 5:03pm, Jeff Schwab <j...@schwabcenter.com> wrote:
> Ian Collins wrote:
> > Jeff Schwab wrote:
> >> Pete Becker wrote:
> >>> On 2008-10-09 09:33:41 -0400, "A.Leopold"
> >>> <andreas.leop...@himt.de> said:

> >>>> is there a c++ equivalent function to the c-function 'sprintf'?

> >>> Yes. Its name is sprintf.
> >> Assuming that line is preceded by "using std::sprintf;".

> > That depends on which header you include. From what I've seen, people
> > still prefer <stdio.h> over <cstdio>.

> Where are you seeing this?

Probably in shops which prefer libraries which work as
specified.

> IME, it's vanishingly rare, and generally a sign of
> incompetence.

Using a library which works as specified is incompetent? Using
one that doesn't isn't? Implementations where the <c...>
libraries work as specified are so rare that the standards
committee changed the specification.

--
James Kanze (GABI Software) email:james.kanze@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34