@@ -3221,8 +3221,13 @@ of the pragma in the :title:`GNAT_Reference_manual`).
This switch activates warnings on component clauses in record
representation clauses that leave holes (gaps) in the record layout.
- If this warning option is active, then record representation clauses
- should specify a contiguous layout, adding unused fill fields if needed.
+ If a record representation clause does not specify a location for
+ every component of the record type, then the warnings generated (or not
+ generated) are unspecified. For example, there may be gaps for which
+ either no warning is generated or a warning is generated that
+ incorrectly describes the location of the gap. This undesirable situation
+ can sometimes be avoided by adding (and specifying the location for) unused
+ fill fields.
.. index:: -gnatw.H (gcc)
@@ -19,7 +19,7 @@
@copying
@quotation
-GNAT User's Guide for Native Platforms , Nov 14, 2022
+GNAT User's Guide for Native Platforms , Nov 18, 2022
AdaCore
@@ -11305,8 +11305,13 @@ This switch suppresses warnings on hiding declarations.
This switch activates warnings on component clauses in record
representation clauses that leave holes (gaps) in the record layout.
-If this warning option is active, then record representation clauses
-should specify a contiguous layout, adding unused fill fields if needed.
+If a record representation clause does not specify a location for
+every component of the record type, then the warnings generated (or not
+generated) are unspecified. For example, there may be gaps for which
+either no warning is generated or a warning is generated that
+incorrectly describes the location of the gap. This undesirable situation
+can sometimes be avoided by adding (and specifying the location for) unused
+fill fields.
@end table
@geindex -gnatw.H (gcc)
From: Steve Baird <baird@adacore.com> The -gnatw.h option enables warnings about "gaps" in record layout specifications. In the case of a "partial" layout specification, where the locations of some components are left unspecified, the resulting warnings may be incomplete or incorrect. Document this implementation limitation. gcc/ada/ * doc/gnat_ugn/building_executable_programs_with_gnat.rst: Improve the description of how the -gnatw.h switch interacts with "partial" record layout specifications (i.e., specifications where the locations of some components are left unspecified). * gnat_ugn.texi: Regenerate. Tested on x86_64-pc-linux-gnu, committed on master. --- .../building_executable_programs_with_gnat.rst | 9 +++++++-- gcc/ada/gnat_ugn.texi | 11 ++++++++--- 2 files changed, 15 insertions(+), 5 deletions(-)