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https://issues.apache.org/jira/browse/STDCXX-241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Martin Sebor updated STDCXX-241:
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Summary: [LWG #136] std::istream::seekg problem (was: std::istream::seekg
problem (LWG issue 136))
Used the [LWG NN] convention in Summary line to refer to Library Working Group
issue number 136:
http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#136
> [LWG #136] std::istream::seekg problem
> --------------------------------------
>
> Key: STDCXX-241
> URL: https://issues.apache.org/jira/browse/STDCXX-241
> Project: C++ Standard Library
> Issue Type: Bug
> Components: 27. Input/Output
> Affects Versions: 4.1.3, 4.1.2
> Environment: all
> Reporter: Martin Sebor
>
> Moved from the Rogue Wave bug tracking database:
> Class/File:
> Fix Priority: Must Fix
> Long Description:
> *** Nov 10 1999 9:33PM *** sebor ***
> Problem: seekg - problem
> see seek2.cpp:
> The ANSI/ISO-C++ document(ISO/IEC 14882:1998(E)) states about the effects of
> seekg:
> ANSI> Effects: If fail() != true, executes rdbuf()í>pubseekpos( pos).
> (The RW-Implementation instead executes rdbuf()->pubseekpos(pos,
> ios_base::in);)
> pubseekpos calls seekpos which is declared:
> pos_type seekpos(pos_type sp, ios_base::openmode which
> = ios_base::in | ios_base::out);
> since the 2nd Argument (which) is not given in the above call of pubseekpos
> the value of the which-Argument is the default value ios_base::in |
> ios_base::out.
> seekpos should alter both the position in the input and the output sequence
> in this case.
> The RW-Implementation alters only the position in the input-sequence.
> Though the RW-implementation seems to be intuitivly right, it is formally
> not conforming.
> I think RogueWave should support the lwg issue No 136 described in
> http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/lwg-issues.html#136
> TEST CASE:
> #include <string>
> #include <sstream>
> #include <iostream>
> using namespace std;
> typedef basic_stringbuf<char, char_traits<char>, allocator<char> > buffer;
> typedef basic_istream<char, char_traits<char> > input_stream;
> typedef char_traits <char> traits;
> typedef char_traits<char>::pos_type pos_type;
> #define VERIFY(p1,p2) verify(p1,p2,__LINE__)
> template <class T> void verify (T p1, T p2, int line)
> {
> if(p1 != p2) {
> cerr << "line " << line << ": " << p1 << " should be "
> << p2 << '\n';
> }
> }
> template <> void verify (string p1, string p2, int line)
> {
> if(p1 != p2) {
> cerr << "line " << line << ": \"" << p1 << "\" should be \""
> << p2 << "\" \n";
> }
> }
> int main()
> {
> const string expstr ("Rogue Wave");
> buffer buf (expstr, ios_base::in | ios_base::out);
> typedef basic_iostream<char, char_traits<char> > iostrm;
>
> iostrm iostobj(&buf);
> char s[80];
>
> VERIFY ((void *)iostobj.rdbuf(),(void *)&buf);
> VERIFY (iostobj.gcount(),streamsize(0));
>
> iostobj >> s;
> VERIFY (string(s), string("Rogue"));
> iostobj.get (s, sizeof s);
> VERIFY (string(s), string(" Wave"));
> iostobj.clear ();
> iostobj.seekg (0, ios::end);
> iostobj.write (" Software", 9);
> iostobj.seekp (0);
> iostobj.get (s, sizeof s);
> iostobj.clear ();
> VERIFY (string(s), string("Rogue Wave Software"));
> }
> CC -c -mt -D_RWSTD_USE_CONFIG -I/amd/devco/sebor/dev/stdlib/include
> -I/build/seb
> or/sunpro-5.8.j1-12d/include -I/amd/devco/sebor/dev/stdlib/examples/include
> -li
> brary=%none -O +w t.cpp
> CC t.o -o t -library=%none -L/build/sebor/sunpro-5.8.j1-12d/lib -mt
> -L/build/s
> ebor/sunpro-5.8.j1-12d/lib -lstd12d -lm
> line 55: " Software" should be "Rogue Wave Software"
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