https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65022
Bug ID: 65022
Summary: basic_string operator
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: critical
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: wbrana at gmail dot com
operators don't return reference if out of range
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4296.pdf
21.4.5 basic_string element access [string.access]
const_reference operator[](size_type pos) const;
reference operator[](size_type pos);
1 Requires: pos <= size().
2 Returns: *(begin() + pos) if pos < size(). Otherwise, returns a reference to
an object of type
charT with value charT(), where modifying the object leads to undefined
behavior.
3 Throws: Nothing.
4 Complexity: Constant time.
https://gcc.gnu.org/git/?p=gcc.git;a=blob_plain;f=libstdc%2B%2B-v3/include/bits/basic_string.h;hb=HEAD
// Element access:
/**
* @brief Subscript access to the data contained in the %string.
* @param __pos The index of the character to access.
* @return Read-only (constant) reference to the character.
*
* This operator allows for easy, array-style, data access.
* Note that data access with this operator is unchecked and
* out_of_range lookups are not defined. (For checked lookups
* see at().)
*/
const_reference
operator[] (size_type __pos) const
{
_GLIBCXX_DEBUG_ASSERT(__pos <= size());
return _M_data()[__pos];
}
/**
* @brief Subscript access to the data contained in the %string.
* @param __pos The index of the character to access.
* @return Read/write reference to the character.
*
* This operator allows for easy, array-style, data access.
* Note that data access with this operator is unchecked and
* out_of_range lookups are not defined. (For checked lookups
* see at().) Unshares the string.
*/
reference
operator[](size_type __pos)
{
// allow pos == size() as v3 extension:
_GLIBCXX_DEBUG_ASSERT(__pos <= size());
// but be strict in pedantic mode:
_GLIBCXX_DEBUG_PEDASSERT(__pos < size());
_M_leak();
return _M_data()[__pos];
}
