[STDCXX-67] std::istream::getline(buffer, 0) writes past the end of buffer

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 4.1.2
• Fix Version/s: 4.1.3
• Component/s: 27. Input/Output

Environment

all

• Assignee: Martin Sebor
• Reporter: Martin Sebor
• Created: 17/Nov/05 08:17
• Updated: 22/Apr/08 01:57
• Resolved: 09/Dec/05 10:28

Description

The program below aborts on line 20 on all platforms indicating that std::istream::getline(buffer, 0) writes past the end of the zero-size buffer.

$ cat -n t.cpp && nice gmake t -r && ./t
1 #include <cassert>
2 #include <sstream>
3
4 int main ()
5 {
6 std::istringstream strm ("\n\n");
7
8 char s [3] =

{ 'x', 'y', 'z' }

;
9
10 strm.getline (s, 0);
11
12 // 27.6.1.3, p17, bullet 2:
13 // Characters are extracted and stored until c == delim for the next
14 // available input character c.
15
16 assert (strm.goodbit == strm.rdstate ());
17 assert (1 == strm.gcount ());
18 assert ('x' == s [0]);
19 assert ('y' == s [1]);
20 assert ('z' == s [2]);
21
22 strm.getline (s, 1);
23
24 // 27.6.1.3, p17, bullet 3:
25 // Characters are extracted and stored until (n - 1) characters
26 // are stored (in which case the function calls setstate(failbit)).
27 // p20:
28 // In any case, it then stores a null character (using charT()) into
29 // the next successive location of the array.
30
31 assert (strm.goodbit == strm.rdstate ());
32 assert (1 == strm.gcount ());
33 assert ('\0' == s [0]);
34 assert ('y' == s [1]);
35 assert ('z' == s [2]);
36
37 strm.clear ();
38 strm.getline (s, 2);
39
40 // 27.6.1.3, p17, bullet 1:
41 // Characters are extracted and stored until end-of-file occurs on
42 // the input sequence (in which case the function calls setstate(eofbit))
43 // p20:
44 // In any case, it then stores a null character (using charT()) into
45 // the next successive location of the array.
46
47 assert ((strm.eofbit | strm.failbit) == strm.rdstate ());
48 assert (0 == strm.gcount ());
49 assert ('\0' == s [0]);
50 assert ('y' == s [1]);
51 assert ('z' == s [2]);
52 }
aCC -c -D_RWSTDDEBUG -mt -D_RWSTD_USE_CONFIG -I/build/sebor/aCC-6.0-15S/include -I/build/sebor/dev/stdlib/include -I/build/sebor/dev/stdlib/../rwtest -I/build/sebor/dev/stdlib/../rwtest/include -I/build/sebor/dev/stdlib/tests/include -AA -g +d +DD64 +w +W392 +W655 +W684 +W818 +W819 +W849 +W2193 +W2236 +W2261 +W2340 +W2401 +W2487 t.cpp
aCC t.o -o t -L/build/sebor/aCC-6.0-15S/rwtest -lrwtest15S -AA +nostl -Wl,+s -L/build/sebor/aCC-6.0-15S/lib -mt +DD64 -L/build/sebor/aCC-6.0-15S/lib -lstd15S -lm
Assertion failed: 'z' == s [2], file t.cpp, line 20
ABORT instruction (core dumped)