http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52938
Bug #: 52938
Summary: std::string::reserve request is not maintained if
object is used in other object copy ctore
Classification: Unclassified
Product: gcc
Version: 4.6.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: abdul.toh...@emc.com
In the line below I use 2 std::string (x and y) and I call x.reserve. But I
found out that if I create string y from x (using copy ctor), the reserved
capacity is transferred to y and it is no longer associated with x.
std::string x;
x.reserve(20); /// x capacity is 20
std::cout<<x.capacity()<<' '<<(void*)(x.c_str())<<"\n";
std::string y(x);
x="aaa"; /// x capacity should = 20
std::cout<<x.capacity()<<' '<<(void*)(x.c_str())<<"\n";
x += "bbb"; /// x capacity should = 20
std::cout<<x.capacity()<<' '<<(void*)(x.c_str())<<"\n";
compile and run:
20 0xf40028
3 0xf40068
6 0xf40098
Notice how the pointer to string buffer is being reallocated (it shouldn't
since I have asked for x.reserve(20).
The code will behave correctly if I remove the line std::string y(x).
BTW, MS Visual c++ handles this correctly.
