diff options
| -rw-r--r-- | doc/src/snippets/code/src_corelib_tools_qbytearray.cpp | 17 | ||||
| -rw-r--r-- | src/corelib/tools/qbytearray.cpp | 23 |
2 files changed, 35 insertions, 5 deletions
diff --git a/doc/src/snippets/code/src_corelib_tools_qbytearray.cpp b/doc/src/snippets/code/src_corelib_tools_qbytearray.cpp index 736394f..3cd3db8 100644 --- a/doc/src/snippets/code/src_corelib_tools_qbytearray.cpp +++ b/doc/src/snippets/code/src_corelib_tools_qbytearray.cpp @@ -401,5 +401,22 @@ QByteArray text = QByteArray::fromHex("517420697320677265617421"); text.data(); // returns "Qt is great!" //! [45] +//! [46] +QString tmp = "test"; +QByteArray text = tmp.toLocal8Bit(); +char *data = new char[text.size()] +strcpy(data, text.data()); +delete [] data; +//! [46] + +//! [47] +QString tmp = "test"; +QByteArray text = tmp.toLocal8Bit(); +char *data = new char[text.size() + 1] +strcpy(data, text.data()); +delete [] data; +//! [47] + } + diff --git a/src/corelib/tools/qbytearray.cpp b/src/corelib/tools/qbytearray.cpp index c4a84fc..d2fbf5a 100644 --- a/src/corelib/tools/qbytearray.cpp +++ b/src/corelib/tools/qbytearray.cpp @@ -903,8 +903,8 @@ QByteArray &QByteArray::operator=(const char *str) The last byte in the byte array is at position size() - 1. In addition, QByteArray ensures that the byte at position size() is always '\\0', so that you can use the return value of data() and - constData() as arguments to functions that expect - '\\0'-terminated strings. + constData() as arguments to functions that expect '\\0'-terminated + strings. Example: \snippet doc/src/snippets/code/src_corelib_tools_qbytearray.cpp 6 @@ -997,7 +997,9 @@ QByteArray &QByteArray::operator=(const char *str) Returns a pointer to the data stored in the byte array. The pointer can be used to access and modify the bytes that compose - the array. The data is '\\0'-terminated. + the array. The data is '\\0'-terminated, i.e. the number of + bytes in the returned character string is size() + 1 for the + '\\0' terminator. Example: \snippet doc/src/snippets/code/src_corelib_tools_qbytearray.cpp 8 @@ -1009,6 +1011,16 @@ QByteArray &QByteArray::operator=(const char *str) This function is mostly useful to pass a byte array to a function that accepts a \c{const char *}. + The following example makes a copy of the char* returned by + data(), but it will corrupt the heap and cause a crash because it + does not allocate a byte for the '\\0' at the end: + + \snippet doc/src/snippets/code/src_corelib_tools_qbytearray.cpp 46 + + This one allocates the correct amount of space: + + \snippet doc/src/snippets/code/src_corelib_tools_qbytearray.cpp 47 + Note: A QByteArray can store any byte values including '\\0's, but most functions that take \c{char *} arguments assume that the data ends at the first '\\0' they encounter. @@ -1591,8 +1603,9 @@ QByteArray& QByteArray::append(const char *str) array and returns a reference to this byte array. If \a len is negative, the length of the string will be determined - automatically using qstrlen(). If \a len is zero or the length of the - string is zero, nothing will be appended to the byte array. + automatically using qstrlen(). If \a len is zero or \a str is + null, nothing is appended to the byte array. Ensure that \a len is + \e not longer than \a str. */ QByteArray &QByteArray::append(const char *str, int len) |