The C standard does not specify whether the underlying type of an enum
is signed or unsigned, and until C23 there was no way to control this
explicitly. GCC appears to make enums unsigned unless there is a
negative value among cases of the enum, in which case it becomes signed.
MSCV appears to make enums signed by default.
A bitfield of an enum type (which is not specificied in the C standard
either) behaves as if it was an instance of a numeric type with a
reduced value range. Specifically, a 'signed int val : 2;' bitfield will
have the possible values of -2, -1, 0, and 1, with the usual wraparound
behavior for the values that don't fit (although this too is
implementation-defined).
This causes the following issue, if we have:
typedef enum
{
G_ZERO,
G_ONE,
G_TWO
} GFoo;
struct _GBar
{
GFoo foo : 2;
};
and then assign bar.foo = G_TWO and read it back, it will have the
expected value of 2 (aka G_TWO) on GCC, but a value of -2 (not matching
any of the enum variants) on MSVC.
There does not seem to be any way to influence signedness of an enum
prior to C23, nor is there a 'unsigned GFoo foo : 2;' syntax. The only
remaining options seems to be never using enums in bitfields, which is
what this change implements.
This corresponds to https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/6467
in GTK.
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Add SPDX license (but not copyright) headers to all files which follow a
certain pattern in their existing non-machine-readable header comment.
This commit was entirely generated using the command:
```
git ls-files gio/*.[ch] | xargs perl -0777 -pi -e 's/\n \*\n \* This library is free software; you can redistribute it and\/or\n \* modify it under the terms of the GNU Lesser General Public/\n \*\n \* SPDX-License-Identifier: LGPL-2.1-or-later\n \*\n \* This library is free software; you can redistribute it and\/or\n \* modify it under the terms of the GNU Lesser General Public/igs'
```
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #1415
2007-12-14 Alexander Larsson <alexl@redhat.com>
* Makefile.am:
* gfileattribute.[ch]:
* gfileattribute-priv.h:
Move GFileAttributeValue to a private header, as
its sort of ugly.
* gfile.[ch]:
Make set_attribute take a type + a pointer instead
of a GFileAttributeValue.
* gfileinfo.[ch]:
Fix up for above changes.
Add g_file_info_get_attribute_data to get
all info in one call, g_file_info_get_attribute_status
to get the status and g_file_info_get_attribute_as_string.
* gio.symbols:
* glocalfile.c:
* glocalfileinfo.[ch]:
Update for changes
* gunixmounts.c:
Make _guess_type static.
svn path=/trunk/; revision=6129
