Re: Getting incorrect behavior on strstream
Farid Zaripov wrote: -Original Message- From: Jeremy Dean [mailto:[EMAIL PROTECTED] Sent: Friday, June 22, 2007 11:45 PM To: stdcxx-dev@incubator.apache.org Subject: Getting incorrect behavior on strstream I have a testcase that is showing incorrect behavior ostrstream or ostringstream: [...] Any thoughts on this problem? ostrstream::str() returns just the beginning pointer to the sequence. The sequence don't have the null character unless you especially inserted it. You should print no more that otrstream::pcount() characters. See Remarks on the page Better yet, refer to the stdcxx Class Reference :) http://incubator.apache.org/stdcxx/doc/stdlibref/strstreambuf.html#idx1224 Martin
Re: Getting incorrect behavior on strstream
I agree with Farid that test2() and test3() exhibit undefined
behavior because they both fail to append the required NUL to
the string before formatting it via the %s printf directive.
But the test program does demonstrate a real problem, and that
is the formatting of infinity when the stream precision is
greater than 7. It looks as though the num_put facet inserts
the string inf\0\0ity into the stream rather than inf.
A small test case is below.
Please go ahead and open an issue for this in Jira.
Martin
$ cat u.cpp make u ./u | od -c
#include cassert
#include iostream
#include sstream
int main () {
std::ostringstream s;
s.precision (8);
s 1 / 0.0;
std::cout s.str () '\n';
assert (s.str () == inf);
}
gcc -c -I/build/sebor/stdcxx/include/ansi -D_RWSTDDEBUG
-D_RWSTD_USE_CONFIG -I/build/sebor/stdcxx/include
-I/build/sebor/stdcxx-gcc-4.1.0-11s/include
-I/build/sebor/stdcxx/examples/include -pedantic -nostdinc++ -g -W
-Wall -Wcast-qual -Winline -Wshadow -Wwrite-strings -Wno-long-long u.cpp
u.cpp: In function 'int main()':
u.cpp:8: warning: division by zero in '1 / 0.'
gcc u.o -o u -L/build/sebor/stdcxx-gcc-4.1.0-11s/lib -lstd11s -lsupc++
-lm
Assertion failed: s.str () == inf, file u.cpp, line 10
000 i n f \0 \0 i t y \n
011
Jeremy Dean wrote:
I have a testcase that is showing incorrect behavior ostrstream or
ostringstream:
#include cstdio
#include iostream
#include iomanip
#include sstream
#include strstream
#include cmath
void test1() {
std::ostringstream S;
long double x = std::pow(1e300,2);
S Somethingstd::setprecision(8) x;
S else;
std::printf(Test1: %s\n, S.str().c_str());
}
void test2() {
std::ostrstream S;
long double x = std::pow(1e300,2);
S Something std::setprecision(7) x;
S else;
std::printf(Test2: %s\n, S.str());
}
void test3() {
std::ostrstream S;
long double x = 0.0/0.0;
S Something std::setprecision(8) x;
S else;
std::printf(Test3: %s\n, S.str());
}
int main(int argc, char* argv[]) {
test1();
test2();
test3();
}
On solaris 8 with Sun Studio 8 patch 14 I get the following output
Test1: Something inf
Test2: Something inf else else
Test3: Something nan else
Test1 is missing else
Test2 has an extra else
Test3 looks ok.
On RedHat 3u6 I get the following output:
Test1: Something inf else
Test2: Something inf else
Test3: Something nan elseing inf else
Test1 and 2 look ok
Test3 however has extra output ing inf else
Any thoughts on this problem?
Thanks,
Jeremy
Jeremy Dean
Rogue Wave Software,
A QUOVADX(tm) division
Technical Support
Phone: 303-545-3205 -- 1-800-404-4767
E-mail: [EMAIL PROTECTED]
Web: http://www.roguewave.com/support
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http://www.roguewave.com/kbdocs/search.html
View issues online at:
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RE: Getting incorrect behavior on strstream
Ok, so I added the S std::ends; to each of the stream statements.
This did resolve it on Red hat, however on Solaris for the first
testfunction it did not:
void test1() {
std::ostringstream S;
long double x = std::pow(1e300,2);
S Somethingstd::setprecision(8) x;
S else;
S std::ends;
std::printf(Test1: %s\n, S.str().c_str());
}
On solaris it is printing up until the double and then nothing else is
printed. However if I change the precision to less then 8 then it works
fine.
Jeremy
-Original Message-
From: Martin Sebor [mailto:[EMAIL PROTECTED]
Sent: Monday, June 25, 2007 11:36 AM
To: stdcxx-dev@incubator.apache.org
Subject: Re: Getting incorrect behavior on strstream
Farid Zaripov wrote:
-Original Message-
From: Jeremy Dean [mailto:[EMAIL PROTECTED]
Sent: Friday, June 22, 2007 11:45 PM
To: stdcxx-dev@incubator.apache.org
Subject: Getting incorrect behavior on strstream
I have a testcase that is showing incorrect behavior ostrstream or
ostringstream:
[...]
Any thoughts on this problem?
ostrstream::str() returns just the beginning pointer to the
sequence.
The sequence don't
have the null character unless you especially inserted it. You should
print no more that
otrstream::pcount() characters.
See Remarks on the page
Better yet, refer to the stdcxx Class Reference :)
http://incubator.apache.org/stdcxx/doc/stdlibref/strstreambuf.html#idx12
24
Martin
Getting incorrect behavior on strstream
I have a testcase that is showing incorrect behavior ostrstream or
ostringstream:
#include cstdio
#include iostream
#include iomanip
#include sstream
#include strstream
#include cmath
void test1() {
std::ostringstream S;
long double x = std::pow(1e300,2);
S Somethingstd::setprecision(8) x;
S else;
std::printf(Test1: %s\n, S.str().c_str());
}
void test2() {
std::ostrstream S;
long double x = std::pow(1e300,2);
S Something std::setprecision(7) x;
S else;
std::printf(Test2: %s\n, S.str());
}
void test3() {
std::ostrstream S;
long double x = 0.0/0.0;
S Something std::setprecision(8) x;
S else;
std::printf(Test3: %s\n, S.str());
}
int main(int argc, char* argv[]) {
test1();
test2();
test3();
}
On solaris 8 with Sun Studio 8 patch 14 I get the following output
Test1: Something inf
Test2: Something inf else else
Test3: Something nan else
Test1 is missing else
Test2 has an extra else
Test3 looks ok.
On RedHat 3u6 I get the following output:
Test1: Something inf else
Test2: Something inf else
Test3: Something nan elseing inf else
Test1 and 2 look ok
Test3 however has extra output ing inf else
Any thoughts on this problem?
Thanks,
Jeremy
Jeremy Dean
Rogue Wave Software,
A QUOVADX(tm) division
Technical Support
Phone: 303-545-3205 -- 1-800-404-4767
E-mail: [EMAIL PROTECTED]
Web: http://www.roguewave.com/support
Knowledge Base entries:
http://www.roguewave.com/kbdocs/search.html
View issues online at:
http://www.roguewave.com/youraccount/login/
