3 ms·

I disagree. I avoid implicit casting, including truthiness. "== true" is indeed suspicious because you aren't avoiding anything, but to me "!= 0" or "!= nullptr

I disagree. I avoid implicit casting, including truthiness. "== true" is indeed suspicious because you aren't avoiding anything, but to me "!= 0" or "!= nullptr" are crisper.

userbinator 4y ago
I don't know what you mean by "crisper", but in general I've noticed that extraneous code only increases the chance of bugs (and this is a good example of that.) if(foo) and if(!foo) are very common idioms and should be committed to the subconscious memory.
WirelessGigabit 4y ago
!= 0 should only be used for ints / floats / 'numbers'. Comparing it to false requires me to know that false is 0. Comparing it to a ptr requires me to know that 0 represents a pointer pointing to nothing.
djur 4y ago
0 is the false value in C, no implicit casting or "truthiness" involved. The C standard explicitly defines if statements in terms of zero: "the first substatement is executed if the expression compares unequal to 0... [else] is executed if the expression compares equal to 0". C does not have a boolean type. (The `true` and `false` defined in stdbool.h are macros expanding to the integer literals 1 and 0, respectively.)
- 3836293648 4y ago
  C has a boolean type, it just doesn't have true and false constants in that type.
- pjmlp 4y ago
  C23 replaces them with proper keywords.
  - djur 4y ago
    Yes, although they still evaluate to 0 and 1 and conditional logic is still defined in terms of 0 and 1. Maybe that will change at some point in the future as well!
- UncleEntity 4y ago
  They aren’t testing for ‘false’ in this case but for success. Functions which return 0 on success I always compare with 0 as “if (foo()) error();” easily gets confusing. If I see “if (foo() != 0) error();” then I can easily tell what’s going on because C is funny like that. Conversely, if I’m testing for truthfulness or NULL I’ll use the boolean operators.

I disagree. I avoid implicit casting, including truthiness. "== true" is indeed suspicious because you aren't avoiding anything, but to me "!= 0" or "!= nullptr" are crisper.

userbinator 4y ago

I don't know what you mean by "crisper", but in general I've noticed that extraneous code only increases the chance of bugs (and this is a good example of that.) if(foo) and if(!foo) are very common idioms and should be committed to the subconscious memory.

WirelessGigabit 4y ago

!= 0 should only be used for ints / floats / 'numbers'. Comparing it to false requires me to know that false is 0. Comparing it to a ptr requires me to know that 0 represents a pointer pointing to nothing.

djur 4y ago

0 is the false value in C, no implicit casting or "truthiness" involved. The C standard explicitly defines if statements in terms of zero: "the first substatement is executed if the expression compares unequal to 0... [else] is executed if the expression compares equal to 0". C does not have a boolean type. (The `true` and `false` defined in stdbool.h are macros expanding to the integer literals 1 and 0, respectively.)

3836293648 4y ago
C has a boolean type, it just doesn't have true and false constants in that type.
pjmlp 4y ago
C23 replaces them with proper keywords.
- djur 4y ago
  Yes, although they still evaluate to 0 and 1 and conditional logic is still defined in terms of 0 and 1. Maybe that will change at some point in the future as well!
UncleEntity 4y ago
They aren’t testing for ‘false’ in this case but for success. Functions which return 0 on success I always compare with 0 as “if (foo()) error();” easily gets confusing. If I see “if (foo() != 0) error();” then I can easily tell what’s going on because C is funny like that. Conversely, if I’m testing for truthfulness or NULL I’ll use the boolean operators.