Re:Clang is better than GCC
by Stratoscope on Sunday November 27, 2022 @09:29PM
(#33769196)
When I used to write a lot of C code, my solution for this was to avoid calling memcmp() directly at all when I only cared about a yes/no on the match. Instead I used a wrapper I called memeq():
int memeq( const void* lhs, const void* rhs, size_t count ) {
return memcmp( lhs, rhs, count ) == 0;
}
I would also use a typedef for the struct, so you don't have to keep writing "struct" everywhere:
typedef struct {
int x, y, z;
} tmp;
if( ! memeq( m_result_original, m_result_my_version, sizeof(tmp) ) )
1. There are similar functions (like std::lexicographical_compare() in C++) returning bool instead an int.
2. It's not crazy to read memcmp() as comparing for equality rather than ordering. i.e. I think when you see 'if (memcmp(a, b, n))', it's quite natural for one's brain to read it as "if a and b are equal..."
For someone who uses memcmp() on a daily basis, you probably don't encounter these misconceptions. But as someone who writes C++ and merely deals with C once in a while in the process, both of these possibilities have tripped me up multiple times when seeing if (memcmp(...)). Writing != 0 has always cleared that confusion for me, since it immediately signals the result (a) isn't meant to be read as a Boolean, and (b) might be negative, thus putting my brain on alert.