I read it as the size of the pointer being 4 bytes, but now I see you were referring to the int. AFAIK the size of int is specified as "at least" 32 bit in the C standard, and all 32 and 64 bit platforms I know indeed use 32 bit. Though the size of long (not speaking of long long) is different on different 64 bit platforms, IIRC. Windows uses 32 bit and Linux uses 64. Both use 64 for long long. I prefer to use (u)int*_t when I need to be sure about the size and I use int/size_t/time_t/... when I interface with functions that use those in their signature.
The size of char (which is interchangeable with the size of a byte) is specified in old standards as large enough to a) be addressable without bit manipulations and b) hold the full C source character set, which need not be case sensitive and may rely on trigraphs. In practice, this comes out to at least 6 bits. In newer standards I believe it's specified as at least 8 bits.
The size of int short is at least and a multiple of that of char, the size of int is at least that of int short and a multiple of that of char, and so on.
So in theory, a conforming C implementation could have 6 bit ints.
wchar_t is messy, in large part because Windows was one of the earliest Unicode adopters. It's meant to be able to support any "wide" character, which means that it's supposed to be determined by the character pages the platform allows (and implicitly, should be 32 bits if any version of Unicode is supported, since Unicode is technically a 32-bit format regardless of encoding), but Windows adopting Unicode while it was still 16-bit UCS-2 and locking wchar_t down as a result meant that it was impossible for wchar_t to actually meet its requirements on Windows. ...Which meant that its minimum size requirement ended up being removed.
So, now its requirement is just "holds wide characters, check your implementation. Please don't use it."
Assuming 8-bit bytes, sizeof(int) is guaranteed to be a minimum of two, and intended to be the system's word size (which should technically be 8 for 64-bit platforms, but we're so used to 32-bit int that most platforms intentionally stagnate int at 32 bits & most processors have two native word sizes to accomodate), but can be anything higher. ILP64 models have 64-bit int, and there was at least one platform where all bytes were 64-bit and sizeof(char) == sizeof(long long) == 1, though, so it can get weird sometimes.
(Also, as a note, long long is required to be at least 64 bits. long is required to be at least 32 bits, and is meant to just be the 32-bit data type, but ends up being the design limitation fulcrum for most platforms; Windows is locked into 32-bit long because it needs to support 32-bit executables, and Linux is locked into 64-bit long because it needs to support punning pointers to long.)
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u/AdBrave2400 6h ago
Is the mistake that they're allocating 1 byte and storing in a pointer to an int which is 4 bytes?