Hi,
On 13-08-19 23:31, Antonio Quartulli wrote:
> On 13/08/2019 23:26, David Sommerseth wrote:
>> wouldn't it be better to
>> do 'if (rgi6->iface[0])' instead? Since the buffer should be NULL terminated
>> and has to be NULL terminted for strlen() to function anyhow. But the
>> compiled code would be a bit more efficient (even though, this isn't
>> necessarily a performance critical code section).
>
> In my opinion strlen() is more readable for the casual developer
> checking this code. Behind iface[0] we may hide other ambiguous
> assumptions (even though this is not the case here, but we won't
> remember in some months from now).
Antionio's answer is of course the real reason to use strlen(), but you
nerd-sniped me by saying "compiled code would be a bit more efficient".
As you said, that wouldn't matter here, but still: compilers nowadays do
optimize calls to strlen, memset, memcpy, etc.
The following code
#include <string.h>
int test(const char *buf) {
return (strlen(buf) > 0);
}
for example compiles with -O3 on my GCC 8.3 to
0000000000000000 <test>:
0: 31 c0 xor %eax,%eax
2: 80 3f 00 cmpb $0x0,(%rdi)
5: 0f 95 c0 setne %al
8: c3 retq
which indeed just compares the first byte of the buffer against zero.
So, unless there are important performance constraints, let's optimize
code for readability, rather than performance :)
FOOOOM [0]
-Steffan
[0] https://xkcd.com/356/
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