From d8a656d5b6246457e84934bc35115c134bc38def Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Thu, 27 Apr 2023 12:02:38 +0100 Subject: doc: Describe behaviour of enums with fixed underlying type [PR109532] gcc/ChangeLog: PR c++/109532 * doc/invoke.texi (Code Gen Options): Note that -fshort-enums is ignored for a fixed underlying type. (C++ Dialect Options): Likewise for -fstrict-enums. Reviewed-by: Marek Polacek --- gcc/doc/invoke.texi | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 2c525762171..ee78591c73e 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -3495,6 +3495,8 @@ defined in the C++ standard; basically, a value that can be represented in the minimum number of bits needed to represent all the enumerators). This assumption may not be valid if the program uses a cast to convert an arbitrary integer value to the enumerated type. +This option has no effect for an enumeration type with a fixed underlying +type. @opindex fstrong-eval-order @item -fstrong-eval-order @@ -18306,6 +18308,8 @@ Use it to conform to a non-default application binary interface. Allocate to an @code{enum} type only as many bytes as it needs for the declared range of possible values. Specifically, the @code{enum} type is equivalent to the smallest integer type that has enough room. +This option has no effect for an enumeration type with a fixed underlying +type. @strong{Warning:} the @option{-fshort-enums} switch causes GCC to generate code that is not binary compatible with code generated without that switch. -- cgit v1.2.1