Hello.
Alan Stern wrote:
When #include'd alone, <linux/usb/gadget.h> causes a lot of compilation errors
and warnings -- all because it relies on the including code to bring in the
necessary #include's instead of doing this itself.
That's normal,
Right ...
Hardly.
We have different definitions of
normality, it seems. To me, it's not normal when I have to
figure out what to #include in a driver every time just to
satisfy one of the #include's dependencies.
Look at documentation for syscalls and you
will notice they give a list of #includes
which are required. Ergo, "normal".
Give me a list then; document it.
WBR, Sergei
PS: I really didn't expect such opposition to an obvious patch...
My experience has been that .h header files should #include (either
directly or indirectly) enough files to satisfy their own needs,
although not necessarily the needs of the .c files that reference them.
For example, if your .h file defines a structure one of whose members
is a struct device, then your .h file should #include <linux/device.h>.
But if your structure only contains a pointer to a struct device then
this isn't necessary, i.e., the compiler will accept it even though a
.c file using your .h might need to refer to a member of struct device.
I can't help but agree with you.
On the other hand, it's a pain to verify that you have done this. I
guess the easiest way is to write a .c file whose first #include is the
.h file you want to test.
That's how this got discovered, except I wasn't going to test it. :-)
In practice, many of the more-heavily
referenced .h files tend to get #included first in almost every source
file (either directly or indirectly) so the issue hardly ever comes up.
Yes, I guess that's why it doesn't break for the existing drivers. OTOH,
they might have to #include something purely to satisfy gadget.h dependencies.
Alan Stern
WBR, Sergei
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