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N2888 - Exact-width Integer Types May Exceed (u)intmax_tThis creates a problem. How do you portably printf() an integer type that you don’t (and can’t) know the size of, like, say, a uid_t?
Before, when intmax_t was guaranteed to be the largest type, you could reliably and portably cast a uid_t userid to an intmax_t and printf() that: printf(PRIdMAX "\n", (intmax_t)userid);
But now, when any type might be larger than an intmax_t? What do you do?
(The same problem exists when reading an integer string; how do you read, say, a port number, when you don’t know what type in_port_t is? Previously, you could call strtoimax() on the string, detect overflow, and then cast the resulting intmax_t to in_port_t and finally compare for equality to make sure it wasn’t truncated.)
> There is active work in this area to allow us to transition to a better ABI and let these two types live up to their promises
Yes please. Introducing new wider integer types in your CPU, but pretending you haven’t created a new architecture with an associated new ABI, is silly.
This creates a problem. How do you portably printf() an integer type that you don’t (and can’t) know the size of, like, say, a uid_t?
Before, when intmax_t was guaranteed to be the largest type, you could reliably and portably cast a uid_t userid to an intmax_t and printf() that: printf(PRIdMAX "\n", (intmax_t)userid);
But now, when any type might be larger than an intmax_t? What do you do?
(The same problem exists when reading an integer string; how do you read, say, a port number, when you don’t know what type in_port_t is? Previously, you could call strtoimax() on the string, detect overflow, and then cast the resulting intmax_t to in_port_t and finally compare for equality to make sure it wasn’t truncated.)
> There is active work in this area to allow us to transition to a better ABI and let these two types live up to their promises
Yes please. Introducing new wider integer types in your CPU, but pretending you haven’t created a new architecture with an associated new ABI, is silly.