[PATCH] fanotify.3: Pass array to read(2) directly instead of a pointer to it

[PATCH] fanotify.3: Pass array to read(2) directly instead of a pointer to it

[Alejandro Colomar]

It doesn't make any sense to pass a pointer to the array to read(2).

It might make sense to pass a pointer to the first element of the array,
but that is already implicitly done when passing the array, which decays
to that pointer, so it's simpler to pass the array.

And anyway, the cast was unneeded, as any pointer is implicitly casted
to `void *`.

Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
---
 man7/fanotify.7 | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/man7/fanotify.7 b/man7/fanotify.7
index c18ab68ed..c3d40b56d 100644
--- a/man7/fanotify.7
+++ b/man7/fanotify.7
@@ -818,7 +818,7 @@ handle_events(int fd)
 
         /* Read some events */
 
-        len = read(fd, (void *) &buf, sizeof(buf));
+        len = read(fd, buf, sizeof(buf));
         if (len == \-1 && errno != EAGAIN) {
             perror("read");
             exit(EXIT_FAILURE);
@@ -1111,7 +1111,7 @@ main(int argc, char **argv)
 
     /* Read events from the event queue into a buffer */
 
-    len = read(fd, (void *) &events_buf, sizeof(events_buf));
+    len = read(fd, events_buf, sizeof(events_buf));
     if (len == \-1 && errno != EAGAIN) {
         perror("read");
         exit(EXIT_FAILURE);
-- 
2.28.0

Re: [PATCH] fanotify.3: Pass array to read(2) directly instead of a pointer to it

[Alejandro Colomar]

Hi Michael,

I had a typo in the subject.  It's fanotify.7; please fix it when
applying the patch.

Cheers,
Alex

On 9/5/20 1:28 PM, Alejandro Colomar wrote:
> It doesn't make any sense to pass a pointer to the array to read(2).
> 
> It might make sense to pass a pointer to the first element of the array,
> but that is already implicitly done when passing the array, which decays
> to that pointer, so it's simpler to pass the array.
> 
> And anyway, the cast was unneeded, as any pointer is implicitly casted
> to `void *`.
> 
> Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
> ---
>  man7/fanotify.7 | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/man7/fanotify.7 b/man7/fanotify.7
> index c18ab68ed..c3d40b56d 100644
> --- a/man7/fanotify.7
> +++ b/man7/fanotify.7
> @@ -818,7 +818,7 @@ handle_events(int fd)
>  
>          /* Read some events */
>  
> -        len = read(fd, (void *) &buf, sizeof(buf));
> +        len = read(fd, buf, sizeof(buf));
>          if (len == \-1 && errno != EAGAIN) {
>              perror("read");
>              exit(EXIT_FAILURE);
> @@ -1111,7 +1111,7 @@ main(int argc, char **argv)
>  
>      /* Read events from the event queue into a buffer */
>  
> -    len = read(fd, (void *) &events_buf, sizeof(events_buf));
> +    len = read(fd, events_buf, sizeof(events_buf));
>      if (len == \-1 && errno != EAGAIN) {
>          perror("read");
>          exit(EXIT_FAILURE);
> 

Re: [PATCH] fanotify.3: Pass array to read(2) directly instead of a pointer to it

[Michael Kerrisk (man-pages)]

On 9/5/20 1:42 PM, Alejandro Colomar wrote:
> Hi Michael,
> 
> I had a typo in the subject.  It's fanotify.7; please fix it when
> applying the patch.

Patch applied. and title line fixed.

Thanks, Alex.

Cheers,

Michael

> On 9/5/20 1:28 PM, Alejandro Colomar wrote:
>> It doesn't make any sense to pass a pointer to the array to read(2).
>>
>> It might make sense to pass a pointer to the first element of the array,
>> but that is already implicitly done when passing the array, which decays
>> to that pointer, so it's simpler to pass the array.
>>
>> And anyway, the cast was unneeded, as any pointer is implicitly casted
>> to `void *`.
>>
>> Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
>> ---
>>  man7/fanotify.7 | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/man7/fanotify.7 b/man7/fanotify.7
>> index c18ab68ed..c3d40b56d 100644
>> --- a/man7/fanotify.7
>> +++ b/man7/fanotify.7
>> @@ -818,7 +818,7 @@ handle_events(int fd)
>>  
>>          /* Read some events */
>>  
>> -        len = read(fd, (void *) &buf, sizeof(buf));
>> +        len = read(fd, buf, sizeof(buf));
>>          if (len == \-1 && errno != EAGAIN) {
>>              perror("read");
>>              exit(EXIT_FAILURE);
>> @@ -1111,7 +1111,7 @@ main(int argc, char **argv)
>>  
>>      /* Read events from the event queue into a buffer */
>>  
>> -    len = read(fd, (void *) &events_buf, sizeof(events_buf));
>> +    len = read(fd, events_buf, sizeof(events_buf));
>>      if (len == \-1 && errno != EAGAIN) {
>>          perror("read");
>>          exit(EXIT_FAILURE);
>>


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/