diff options
| -rw-r--r-- | doc/README.dev | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/doc/README.dev b/doc/README.dev index 46bc3ca5b..80d502626 100644 --- a/doc/README.dev +++ b/doc/README.dev @@ -501,6 +501,21 @@ Quoted from <http://www.gnu.org/software/gcc/codingconventions.html>: C-Reduce may be useful to try to identify whether a bug comes from the compiler. + ===================================================================== + +To do type punning (i.e. store a value of some type and reinterpret +it as another type), use a union. This is valid in ISO C99 and above +(in C99, see 6.5#7 and Note 82 of 6.5.2.3#3 for the clarification), +but not in C++. So, users of a C++ compilers should make sure that +their compiler supports type punning via a union. If some problem is +reported, we should address it either by making the code compatible +or by adding a configure test to reject the compiler. + +Some references: +* https://en.wikipedia.org/wiki/Type_punning#Use_of_union +* http://stackoverflow.com/questions/346622/opinions-on-type-punning-in-c + "Opinions on type-punning in C++?" + =========================================================================== Avoid variable names "l", "I" and "O", which look like "1" and "0" with |