memcpy only copies first half of wchar_t array

Question

I am encountering an error when I try to use memcpy on a wchar_t string. Specifically, despite the length I am sending in to memcpy being correct for the length of the string I want to copy, only the first half of the characters in the string are copied over. This leaves me with bad data in the target string, since the latter half of the string is full of garbage characters left over from new-ing up the string.

Screenshot below shows the exact problem I am dealing with:

screenshot of code with watches showing the values I get when my code runs The only thing I can think of is that this might be somehow related to me having my locale set to Japanese for non-Unicode applications, but the first thing I did was to change the locale back to English and the problem remains the same. I feel like there is a really obvious solution that I am missing. Any ideas?

Why not read the documentation of `memcpy` rather than guess? — Kerrek SB, Jun 10 '14 at 23:06
Screenshots are much less useful than copy-and-pasted code in text form. — Keith Thompson, Jun 10 '14 at 23:13

score 6 · Accepted Answer · answered Jun 10 '14 at 23:12

6

memcpy takes a number of bytes, not a number of objects
instead of memcpy using wcslen(src) + 1, there is wcscpy
Instead of new wchar_t[] there is std::wstring.

If you had made m_pTextures be a vector of std::wstring then your code would be a whole lot simpler and less prone to errors like this.

answered Jun 10 '14 at 23:12

M.M

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Thank you for the guidance! Honestly, I am very new to C++ so knowing how to make my code simpler and less error-prone is very helpful! – CodeRedd Jun 11 '14 at 23:55

score 3 · Answer 2 · answered Jun 10 '14 at 23:11

As the others have already pointed out, memcpy copies bytes, and wchar_t is more than one byte. Regardless of that, why don't you use some of the existing functions for this? Have a look at wcscpy and the whole lot of functions intended for wchar_t. Start here.

memcpy only copies first half of wchar_t array

2 Answers2