[Qemu-devel] Re: [PATCH 09/15] usb-linux.c: fix warning with _FORTIFY_SOURCE

[Kirill A. Shutemov]

On Tue, Jan 5, 2010 at 4:42 PM, Juan Quintela <address@hidden> wrote:
> "Kirill A. Shutemov" <address@hidden> wrote:
>>   CC    usb-linux.o
>> cc1: warnings being treated as errors
>> usb-linux.c: In function 'usb_host_read_file':
>> usb-linux.c:1204: error: ignoring return value of 'fgets', declared with 
>> attribute warn_unused_result
>> make: *** [usb-linux.o] Error 1
>>
>> Signed-off-by: Kirill A. Shutemov <address@hidden>
>> ---
>>  usb-linux.c |    8 ++++++--
>>  1 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/usb-linux.c b/usb-linux.c
>> index 88728e9..8673474 100644
>> --- a/usb-linux.c
>> +++ b/usb-linux.c
>> @@ -1201,9 +1201,13 @@ static int usb_host_read_file(char *line, size_t 
>> line_size, const char *device_f
>>               device_file);
>>      f = fopen(filename, "r");
>>      if (f) {
>> -        fgets(line, line_size, f);
>> +        if (fgets(line, line_size, f)) {
>> +            ret = 1;
>> +        } else {
>> +            ret = 0;
>> +        }
>> +
> This if is equivalent to:
>
> ret = !!fgets(line, line_size, f);
>
> No need for the if at all :)

It's not very readable.
Probably better to use something like:

ret = (fgets(line, line_size, f) != NULL);