A Philisophical Question

[August Karlstrom]

The variable to_len is clearly supposed to be a length. It
shouldn't be compared to NULL. If we think the 'if' is
necessary, a test that makes more sense would be:

if( to_len > 0 ){
memmove( ptr, l_to, to_len );
ptr += to_len;
}

Yes, of course. I mixed it up with Pete's suggestion to use

if (l_to != NULL) {
memmove(ptr, l_to, to_len);
ptr += to_len;
}


August

 

[Skarmander]

Same here. I see it as a light form of language abuse.

C abuses itself by not having a `nil' keyword. You can pretend NULL is
that keyword for code you write yourself, of course, but since you'll
have to know the full story anyway to read existing code, it doesn't
help much. In any case, this is like brace style: you'll have to decide
for yourself, and as long as you're consistent with the environment
you're working in, it really doesn't matter.

S.

 

[August Karlstrom]

....
C abuses itself by not having a `nil' keyword. You can pretend NULL is
that keyword for code you write yourself, of course, but since you'll
have to know the full story anyway to read existing code, it doesn't
help much. In any case, this is like brace style: you'll have to decide
for yourself, and as long as you're consistent with the environment
you're working in, it really doesn't matter.

The symbol for the nil pointer is not the issue here. If p is a pointer
then I think `if (p != 0) ...' is perfectly OK although I prefer `if (p
!= NULL) ...".


August

 

[Skarmander]

The symbol for the nil pointer is not the issue here. If p is a pointer
then I think `if (p != 0) ...' is perfectly OK although I prefer `if (p
!= NULL) ...".

Ah, but *that* particular wart is the result of C not having a proper
boolean type. It all conspires.

S.

 

[pete]

August Karlstrom wrote:
Ah, but *that* particular wart is the result of C not having a proper
boolean type. It all conspires.

My convention for using

if (x)

instead of

if (x != 0)

is when the meaning of x is boolean in it's nature.
In the below example, it's "while" instead of "if".

int a_toi(const char *nptr)
{
int n;

n = 0;
while (isspace(*nptr)) {
++nptr;
}
if (*nptr != '-') {
if (*nptr == '+') {
++nptr;
}
while (isdigit(*nptr)) {
n = 10 * n - '0' + *nptr++;
}
} else {
++nptr;
while (isdigit(*nptr)) {
n = 10 * n + '0' - *nptr++;
}
}
return n;
}

 

[pete]

(e-mail address removed) wrote:

Say what you mean:

if (to_len != NULL) {

YOU TRICKED ME!!!

 

[August Karlstrom]

My convention for using

if (x)

instead of

if (x != 0)

is when the meaning of x is boolean in it's nature.

Yes, that's certainly the correct way. It's a classical beginners
mistake is to compare a boolean (or in C an int with boolean
interpretation) with a boolean literal.


August