Is 'signed size_t' different from 'ssize_t'?
android, android-ndk
Solution
In Android, `size_t` is `unsigned int`, but `ssize_t` is `long int`. To print or log `ssize_t`, simply use `"%ld"`.
See sys/types.h:
Traditionally, bionic's `ssize_t` was `long int`. This caused GCC to emit warnings when you pass a `ssize_t` to a `printf()`-style function. The correct type is `__kernel_ssize_t`, which is `int`, which isn't an ABI change for C code (because they're the same size) but is an ABI change for C++ because `int` and `long int` mangle to `i` and `l` respectively. So until we can fix the ABI, this change should not be propagated to the NDK.
Note that on other platforms, using `%zd` is preferable.
Problem
When I compile with ndk-build, it shows an error message: warning: format '%zd' expects argument of type 'signed size_t', but argument 5 has type 'ssize_t'. I thought `ssize_t` was the same as `signed size_t`, am I wrong?