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[RFA] comment cleanup in exceptions.[ch]
- From: dje at google dot com (Doug Evans)
- To: gdb-patches at sourceware dot org
- Date: Thu, 4 Dec 2008 13:20:15 -0800 (PST)
- Subject: [RFA] comment cleanup in exceptions.[ch]
Hi.
While looking into using catch_errors/exceptions for something
I ran into some confusing/outdated comments.
I don't know all the details of catch_exceptions to be comfortable
that the result still doesn't have problems, but it is better
than before.
The high order bit here is that I copied the lead paragraph for
catch_exceptions from exceptions.h to exceptions.c and added
a reference back to exceptions.h (it seemed like some text more
than just "see exceptions.h" was useful in exceptions.c),
plus I moved the usage text of MASK to exceptions.h.
I also removed an outdated FIXME regarding utils.c/top.c.
Given that exceptions.[ch] exists I think this FIXME can go.
Ok to check in?
2008-12-04 Doug Evans <dje@google.com>
* exceptions.h: Clean up some comments on catch_exceptions usage.
* exceptions.c: Ditto. Plus mark catch_errors as superseded by
catch_exceptions.
Index: exceptions.c
===================================================================
RCS file: /cvs/src/src/gdb/exceptions.c,v
retrieving revision 1.30
diff -u -p -r1.30 exceptions.c
--- exceptions.c 8 Sep 2008 21:46:21 -0000 1.30
+++ exceptions.c 4 Dec 2008 21:12:21 -0000
@@ -417,25 +417,21 @@ throw_error (enum errors error, const ch
va_end (args);
}
-/* Call FUNC() with args FUNC_UIOUT and FUNC_ARGS, catching any
- errors. Set FUNC_CAUGHT to an ``enum return_reason'' if the
- function is aborted (using throw_exception() or zero if the
- function returns normally. Set FUNC_VAL to the value returned by
- the function or 0 if the function was aborted.
+/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
+ handler. If an exception (enum return_reason) is thrown using
+ throw_exception() than all cleanups installed since
+ catch_exceptions() was entered are invoked, the (-ve) exception
+ value is then returned by catch_exceptions. If FUNC() returns
+ normally (with a positive or zero return value) then that value is
+ returned by catch_exceptions(). It is an internal_error() for
+ FUNC() to return a negative value.
+
+ See exceptions.h for further usage details.
Must not be called with immediate_quit in effect (bad things might
happen, say we got a signal in the middle of a memcpy to quit_return).
This is an OK restriction; with very few exceptions immediate_quit can
- be replaced by judicious use of QUIT.
-
- MASK specifies what to catch; it is normally set to
- RETURN_MASK_ALL, if for no other reason than that the code which
- calls catch_errors might not be set up to deal with a quit which
- isn't caught. But if the code can deal with it, it generally
- should be RETURN_MASK_ERROR, unless for some reason it is more
- useful to abort only the portion of the operation inside the
- catch_errors. Note that quit should return to the command line
- fairly quickly, even if some further processing is being done. */
+ be replaced by judicious use of QUIT. */
/* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with
error() et.al. could maintain a set of flags that indicate the the
@@ -445,10 +441,6 @@ throw_error (enum errors error, const ch
code also randomly used a SET_TOP_LEVEL macro that directly
initialize the longjmp buffers. */
-/* MAYBE: cagney/1999-11-05: Should the catch_errors and cleanups code
- be consolidated into a single file instead of being distributed
- between utils.c and top.c? */
-
int
catch_exceptions (struct ui_out *uiout,
catch_exceptions_ftype *func,
@@ -505,6 +497,8 @@ catch_exceptions_with_msg (struct ui_out
return val;
}
+/* This function is superseded by catch_exceptions(). */
+
int
catch_errors (catch_errors_ftype *func, void *func_args, char *errstring,
return_mask mask)
Index: exceptions.h
===================================================================
RCS file: /cvs/src/src/gdb/exceptions.h,v
retrieving revision 1.22
diff -u -p -r1.22 exceptions.h
--- exceptions.h 1 Jan 2008 22:53:09 -0000 1.22
+++ exceptions.h 4 Dec 2008 21:12:21 -0000
@@ -177,7 +177,7 @@ extern NORETURN void deprecated_throw_re
throw_exception() than all cleanups installed since
catch_exceptions() was entered are invoked, the (-ve) exception
value is then returned by catch_exceptions. If FUNC() returns
- normally (with a postive or zero return value) then that value is
+ normally (with a positive or zero return value) then that value is
returned by catch_exceptions(). It is an internal_error() for
FUNC() to return a negative value.
@@ -191,10 +191,19 @@ extern NORETURN void deprecated_throw_re
copy of the gdb error message. This is used when a silent error is
issued and the caller wants to manually issue the error message.
+ MASK specifies what to catch; it is normally set to
+ RETURN_MASK_ALL, if for no other reason than that the code which
+ calls catch_errors might not be set up to deal with a quit which
+ isn't caught. But if the code can deal with it, it generally
+ should be RETURN_MASK_ERROR, unless for some reason it is more
+ useful to abort only the portion of the operation inside the
+ catch_errors. Note that quit should return to the command line
+ fairly quickly, even if some further processing is being done.
+
FIXME; cagney/2001-08-13: The need to override the global UIOUT
builder variable should just go away.
- This function superseeds catch_errors().
+ This function supersedes catch_errors().
This function uses SETJMP() and LONGJUMP(). */
@@ -225,7 +234,7 @@ extern struct gdb_exception catch_except
indication of the exact exception that it caught - quit_flag might
help.
- This function is superseeded by catch_exceptions(). */
+ This function is superseded by catch_exceptions(). */
typedef int (catch_errors_ftype) (void *);
extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask);