istrstream

Library:  Input/output

istrstream  basic_istream  basic_ios  ios_base 

• Local Index
• Summary
• Synopsis
• Description
• Interface
• Member Types
• Constructors
• Destructors
• Member Functions
• Example
• See Also
• Standards Conformance

Members

char_type int_type istrstream()

off_type pos_type rdbuf()

str() traits_type ~istrstream()

Class that reads characters from an array in memory

#include <strstream>

namespace std {
  class istrstream;
}

The class istrstream reads characters from an array in memory. It uses a private strstreambuf object to control the associated array object. It inherits from basic_istream and therefore can use all the formatted and unformatted input functions.

---

NOTE -- This is a deprecated feature and might not be available in future versions.

---

namespace std {

  class istrstream : public basic_istream<char> {

    public:

      typedef char                            char_type;
      typedef char_traits<char_type>          traits_type;
      typedef typename traits_type::int_type  int_type;
      typedef typename traits_type::pos_type  pos_type;
      typedef typename traits_type::off_type  off_type;

      explicit istrstream(const char *s);
      istrstream(const char *s, streamsize n);
      explicit istrstream(char *s);
      istrstream(char *s, streamsize n);

      virtual ~istrstream();

      strstreambuf *rdbuf() const;
      char *str();

    };
}

char_type

The type char_type is a synonym of type char.

int_type

The type int_type is a synonym of type traits_type::in_type.

off_type

The type off_type is a synonym of type traits_type::off_type.

pos_type

The type pos_type is a synonym of type traits_type::pos_type.

traits_type

The type traits_type is a synonym of type char_traits<char>.

explicit istrstream(const char* s);
explicit istrstream(char* s); 

Constructs an object of class istrstream, initializing the base class basic_istream with the associated strstreambuf object. The strstreambuf object is initialized by calling strstreambuf(s,0), where s designates the first element of an NTBS (null terminated byte string).

explicit istrstream(const char* s, streamsize n);
explicit istrstream(char* s, streamsize n); 

Constructs an object of class istrstream, initializing the base class basic_istream with the associated strstreambuf object. The strstreambuf object is initialized by calling strstreambuf(s,n), where s designates the first element of an array whose length is n elements and n is greater than zero.

virtual ~istrstream();

Destroys an object of class istrstream.

char* 
str();

Calls rdbuf()->str().

strstreambuf* 
rdbuf() const; 

Returns a pointer to the private strstreambuf object associated with the stream.

//
//  istrstream.cpp
//

#include <iostream>    // for cout
#include <strstream>   // for strstream



int main ()
{
    // create two constant istrstream objects and initialize their
    // underlying strstreambufs with string literals; the objects
    // do not create copies of the literals but use them directly
    // for efficiency
    std::istrstream a ("Ce n'est pas l'homme qui prend la mer, ");
    std::istrstream b ("c'est la mer qui prend l'homme.");

    // create a dynamic strstream object
    std::strstream out;

    // output the contents of the streams into out
    out << a.rdbuf () << b.str () << '\n';
  
    // output the contents of out to standard output
    std::cout << out.rdbuf () << '\n';
  
    // output the contents of the stream objects to standard output
    std::cout << a.str () << '\n' << b.rdbuf () << '\n';

    // the dtors of a and b will not release any storage
    // since the objects did not allocate any

    // the dtor of out will release allocated storage since
    // neither freeze() nor str() was called on the object

    return 0;
}


Program Output:

Ce n'est pas l'homme qui prend la mer, c'est la mer qui prend l'homme.

Ce n'est pas l'homme qui prend la mer, 
c'est la mer qui prend l'homme.

char_traits, ios_base, basic_ios, strstreambuf, ostrstream, strstream

Deprecated. See ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Annex D Compatibility features Section D.7.2