DirectXMath.h not self-sufficient on g++ 11.2 (Ubuntu)

[Dennis Bautembach]

Problem

Trying to compile

#include "DirectXMath.h"
int main() { return 0; }

results in the following error output:

/usr/include/c++/11/bits/stl_algo.h: In function ‘_RandomAccessIterator std::__sample(_InputIterator, _InputIterator, std::input_iterator_tag, _RandomAccessIterator, std::random_access_iterator_tag, _Size, _UniformRandomBitGenerator&&)’:
/usr/include/c++/11/bits/stl_algo.h:5758:28: error: expected ‘,’ before ‘++’ token
 5758 |           __out[__sample_sz++] = *__first;
      |                            ^~
      |                            ,
/usr/include/c++/11/bits/stl_algo.h:5758:28: error: expected identifier before ‘++’ token
 5758 |           __out[__sample_sz++] = *__first;
      |                            ^~
/usr/include/c++/11/bits/stl_algo.h: In lambda function:
/usr/include/c++/11/bits/stl_algo.h:5758:32: error: expected ‘{’ before ‘=’ token
 5758 |           __out[__sample_sz++] = *__first;
      |                                ^
/usr/include/c++/11/bits/stl_algo.h: In lambda function:
/usr/include/c++/11/bits/stl_algo.h:5766:24: error: expected ‘{’ before ‘=’ token
 5766 |             __out[__k] = *__first;
      |                        ^
/usr/include/c++/11/bits/stl_algo.h: In function ‘_OutputIterator std::__sample(_ForwardIterator, _ForwardIterator, std::forward_iterator_tag, _OutputIterator, _Cat, _Size, _UniformRandomBitGenerator&&)’:
/usr/include/c++/11/bits/stl_algo.h:5809:28: error: expected primary-expression before ‘=’ token
 5809 |                   *__out++ = *__first;
      |                            ^
/usr/include/c++/11/bits/stl_algo.h:5820:28: error: expected primary-expression before ‘=’ token
 5820 |                   *__out++ = *__first;
      |                            ^
/usr/include/c++/11/bits/stl_algo.h:5833:22: error: expected primary-expression before ‘=’ token
 5833 |             *__out++ = *__first;
      |                      ^
/usr/include/c++/11/bits/stl_algo.h: In function ‘_SampleIterator std::sample(_PopulationIterator, _PopulationIterator, _SampleIterator, _Distance, _UniformRandomBitGenerator&&)’:
/usr/include/c++/11/bits/stl_algo.h:5865:53: error: expected primary-expression before ‘,’ token
 5865 |         __sample(__first, __last, __pop_cat{}, __out, __samp_cat{}, __d,
      |

g++ --version
g++ (Ubuntu 11.2.0-19ubuntu1) 11.2.0

Compile flags: -std=c++20 -O2

Fix

Include <algorithm> before DirectXMath.h:

#include <algorithm>
#include "DirectXMath.h"
int main() { return 0; }

compiles fine. I don't know what standard header DirectXMath actually depends on, it just happens to work with <algorithm>.

[Chuck Walbourn]

The problem is that GNUC's standard C/C++ runtime has some conflicts with Windows SAL annotations required for the library. The workaround for this issue is:

#include <algorithm>
#include <utility>

#include <DirectXMath.h>

This is mentioned in the readme:

https://github.com/microsoft/DirectXMath#compiler-support

Since this does not impact any other toolset (including MinGW on Windows), I do not have these headers included in DirectXMath and I don't actually need them for the library.

[Dennis Bautembach]

Sry completely overlooked that part. Thx for the info!