[PATCH] manual: Fix backtraces code example [BZ #10441]

[PATCH] manual: Fix backtraces code example [BZ #10441]

[Girish Joshi]

From bd99113d312012bde774a66c36b4894355175661 Mon Sep 17 00:00:00 2001
From: Girish Joshi <girish946@gmail.com>
Date: Tue, 10 Mar 2020 17:15:08 +0530
Subject: [PATCH] manual: Fix backtraces code example [BZ #10441]

Validation for pointer returned by backtrace_symbols () added.
Type of variables size and i is changed from size_t to int.

Variable size is used to collect the result from backtrace ()
that is an int. i is the loop counter variable so it can be an int.

Since, size_t size is changed to int size, in printf %zd is changed to %d.
---
 manual/examples/execinfo.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/manual/examples/execinfo.c b/manual/examples/execinfo.c
index a789b6b5a7..01fd2d2dc2 100644
--- a/manual/examples/execinfo.c
+++ b/manual/examples/execinfo.c
@@ -24,17 +24,18 @@ void
 print_trace (void)
 {
   void *array[10];
-  size_t size;
   char **strings;
-  size_t i;
+  int size, i;

   size = backtrace (array, 10);
   strings = backtrace_symbols (array, size);
+  if (strings)
+  {

-  printf ("Obtained %zd stack frames.\n", size);
-
-  for (i = 0; i < size; i++)
-     printf ("%s\n", strings[i]);
+    printf ("Obtained %d stack frames.\n", size);
+    for (i = 0; i < size; i++)
+      printf ("%s\n", strings[i]);
+  }

   free (strings);
 }
-- 
2.21.1


Girish Joshi

Re: [PATCH] manual: Fix backtraces code example [BZ #10441]

[Girish Joshi via Libc-alpha]

Ping.

Girish Joshi


On Tue, Mar 10, 2020 at 9:40 PM Girish Joshi <girish946@gmail.com> wrote:
>
> From bd99113d312012bde774a66c36b4894355175661 Mon Sep 17 00:00:00 2001
> From: Girish Joshi <girish946@gmail.com>
> Date: Tue, 10 Mar 2020 17:15:08 +0530
> Subject: [PATCH] manual: Fix backtraces code example [BZ #10441]
>
> Validation for pointer returned by backtrace_symbols () added.
> Type of variables size and i is changed from size_t to int.
>
> Variable size is used to collect the result from backtrace ()
> that is an int. i is the loop counter variable so it can be an int.
>
> Since, size_t size is changed to int size, in printf %zd is changed to %d.
> ---
>  manual/examples/execinfo.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/manual/examples/execinfo.c b/manual/examples/execinfo.c
> index a789b6b5a7..01fd2d2dc2 100644
> --- a/manual/examples/execinfo.c
> +++ b/manual/examples/execinfo.c
> @@ -24,17 +24,18 @@ void
>  print_trace (void)
>  {
>    void *array[10];
> -  size_t size;
>    char **strings;
> -  size_t i;
> +  int size, i;
>
>    size = backtrace (array, 10);
>    strings = backtrace_symbols (array, size);
> +  if (strings)
> +  {
>
> -  printf ("Obtained %zd stack frames.\n", size);
> -
> -  for (i = 0; i < size; i++)
> -     printf ("%s\n", strings[i]);
> +    printf ("Obtained %d stack frames.\n", size);
> +    for (i = 0; i < size; i++)
> +      printf ("%s\n", strings[i]);
> +  }
>
>    free (strings);
>  }
> --
> 2.21.1
>
>
> Girish Joshi

Re: [PATCH] manual: Fix backtraces code example [BZ #10441]

[DJ Delorie via Libc-alpha]

LGTM but I've noted some suggestions for clarity too.

Reviewed-by: DJ Delorie <dj@redhat.com>


Girish Joshi <girish946@gmail.com> writes:
> Validation for pointer returned by backtrace_symbols () added.

Do we want to add some printf for the "else" case?  I don't think it
adds to the example...

> Type of variables size and i is changed from size_t to int.

Protypes are (stripped):

extern int backtrace (void **__array, int __size);
extern char **backtrace_symbols (void *const *__array, int __size);

So "int" for size is OK.  i loops size, so "int" for i also ok.


>    void *array[10];
> -  size_t size;
>    char **strings;
> -  size_t i;
> +  int size, i;

Ok; prototypes call for "int" not "size_t".

>    size = backtrace (array, 10);
>    strings = backtrace_symbols (array, size);
> +  if (strings)
> +  {

Checking for valid pointer should be "if (strings != NULL)" in our
coding standards, but OK.

> -  printf ("Obtained %zd stack frames.\n", size);
> -
> -  for (i = 0; i < size; i++)
> -     printf ("%s\n", strings[i]);
> +    printf ("Obtained %d stack frames.\n", size);

%zd -> %d, no other changes.

> +    for (i = 0; i < size; i++)
> +      printf ("%s\n", strings[i]);

Indent only, ok.

> +  }

close new block, ok.

Re: [PATCH] manual: Fix backtraces code example [BZ #10441]

[Girish Joshi via Libc-alpha]

Thanks DJ.

Girish Joshi

Re: [PATCH] manual: Fix backtraces code example [BZ #10441]

[Girish Joshi via Libc-alpha]

If this patch is okay, could someone please push it?
Thanks.

Girish Joshi

Re: [PATCH] manual: Fix backtraces code example [BZ #10441]

[Girish Joshi via Libc-alpha]

ping.

Girish Joshi


On Fri, May 8, 2020 at 1:26 AM Girish Joshi <girish946@gmail.com> wrote:
>
> If this patch is okay, could someone please push it?
> Thanks.
>
> Girish Joshi

Re: [PATCH] manual: Fix backtraces code example [BZ #10441]

[Adhemerval Zanella via Libc-alpha]

On 23/05/2020 07:09, Girish Joshi via Libc-alpha wrote:
> ping.
> 
> Girish Joshi
> 
> 
> On Fri, May 8, 2020 at 1:26 AM Girish Joshi <girish946@gmail.com> wrote:
>>
>> If this patch is okay, could someone please push it?
>> Thanks.
>>
>> Girish Joshi

I pushed upstream with DJ suggestion.