Merge pull request #11241 from edubox/feat/libc-future-category

feat(libc): export the error_category members and std::future_error

docs/dev/debt/libc.md

@@ -178,6 +178,7 @@
 - [_WStoul](../../../core/libs/prx/libc/src/Strings.cpp), [_Iswctype](../../../core/libs/prx/libc/src/RuneLocale.cpp), [swscanf_s and swscanf](../../../core/libs/prx/libc/src/ScanningWide.cpp) (libc) - `_WStoul` is `wcstoul` and throws for a base other than 0 or 2 to 36. `_Iswctype` takes the class numbers of Dinkumware's [xwcc.h](https://github.com/superna9999/ti-cgt6x/blob/cgt6x_7_3_4/include/xwcc.h) (1 `alnum` to 11 `xdigit`, 12 `blank`) and throws for any other value, including the FreeBSD masks `wctype` returns; the numbering is not confirmed on the console's `libc.prx`. `swscanf_s` follows C11 7.29.2.2 and K.3.9.1.5, but reads the size argument as `unsigned int` like `sscanf_s` where K.3.9.1.5 specifies `rsize_t`; the console's width is unverified. A runtime-constraint violation (null buffer, format or receiving pointer) only returns `EOF`, and a too small array gets a null first element as in `sscanf_s`. A literal at end of input returns the number of assignments, including zero, rather than `EOF` as FreeBSD does, as reported from the console scanner in #8479; `%%` at end of input still returns `EOF`. A literal mismatch is a matching failure, where FreeBSD's `vfwscanf` reports an input failure. An incomplete floating exponent such as `1e+` converts its mantissa, as reported from the console scanner in #8479; other incomplete exponent forms are not separately verified. A short `%c` field is currently a matching failure without storing its available prefix, while #9321 reports that the console stores a short `%3lc` field; its return count, partial-output extent and precedence are unverified. An integer field that is only a prefix, such as `0x`, does not convert; FreeBSD's `vfwscanf` pushes back the `x` and converts the `0`. Integers out of range are truncated from `strtoll`/`strtoull`. `%p` follows FreeBSD 11's [vfwscanf.c](https://github.com/freebsd/freebsd-src/blob/4ab2e064d7950be84256d671a7ae93f87cc6aa36/lib/libc/stdio/vfwscanf.c#L610-L615): a hexadecimal integer with an optional `0x`, converted as unsigned and stored as a pointer; a length modifier on it throws, where FreeBSD ignores it. `%S` and `%C`, with any length modifier or `*`, end the scan as a matching failure, as the console's Dinkumware scanner in PPSA21564's `libc.prx` treats them as invalid conversions; this was read from the module, not run on a console, and whether input ending before them is an input failure instead is unverified. It throws for unknown length modifiers, scanset ranges, `%n` with suppression or width, and narrow `%s`, `%c` or `%[` input that the C-locale `wcrtomb` cannot convert. `swscanf` runs the same scanner without the size arguments of `%s`, `%c` and `%[`, as FreeBSD's [swscanf.c](https://github.com/freebsd/freebsd-src/blob/d106002967eff712894ab8b5337bbbff106ce5e0/lib/libc/stdio/swscanf.c) passes its arguments to `vswscanf`, so everything above except the sizes applies to it; it also keeps the null buffer, format and receiving pointer checks returning `EOF`, where C leaves those undefined. Neither variant is confirmed on a PS5 title
 - [floating scan errno](../../../core/libs/prx/libc/src/ScanningWide.cpp) (libc) leaves narrow `sscanf` inheriting host `ERANGE` for out-of-range `%f`, `%e` and `%lf`; wide `%Lf` retains host `strtold` errno, so glibc's `ERANGE` for the representable `1e-4950` differs from the bundled library. Wide float and double conversions restore the previous `errno` after `strtof`/`strtod`, as observed in the bundled `libc.prx`; converted values and long-double range handling are retained.
 - [flock](../../../core/libs/prx/libc/src/FileLock.cpp) (libkernel) on Windows shares one lock state between duplicated descriptors, following FreeBSD 11.4's [flock(2)](https://github.com/freebsd/freebsd-src/blob/releng/11.4/lib/libc/sys/flock.2). Independent opens have separate states; closing a descriptor or reopening a stream drops only its reference. Lock transitions on one open file description are serialized. The lock is a host [LockFileEx](https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-lockfileex) lock on one byte at offset 2^63 - 2, which no file reaches, so it excludes other `flock` calls and leaves reads, writes and mapped views alone, like FreeBSD's advisory locks. Console behavior, signal interruption and concurrent closure of a descriptor while its lock call is pending are unverified.
+- [std::error_category, std::future_category and std::future_error](../../../core/libs/prx/libc/src/exception/StandardExceptions.cpp) (libc) - measured from PPSA02530's `libc.prx`, except that the future category's deleting destructor throws instead of freeing it, the string destructor frees the block instead of the console header path, and a `_Doraise` copy of a heap message and header size are unverified. `error_code` keeps the value in the second dword, so `default_error_condition` shifts it into the high half and `equivalent` compares that dword and the category. `_Future_error_category` derives from `_Generic_error_category`, is `future` and maps 1..4 to `broken promise`, `future already retrieved`, `promise already satisfied` and `no state`; other values use the generic map, but `future_error::what()` returns null outside 1..4. `future_error` is 0x40 bytes (vtable, `GuestLocale::String` at 0x8, `error_code` at 0x30). `_Rethrow_future_exception` delegates to `rethrow_exception`.
 - [std::_Throw_Cpp_error](../../../core/libs/prx/libc/src/exception/StandardExceptions.cpp) (libc) follows Dinkumware `thread0.cpp` ([VC12](https://github.com/ganboing/crt.vc12/blob/f1d47126/src/thread0.cpp), [STL](https://github.com/microsoft/STL/blob/da52dc0f/stl/src/thread0.cpp)), without console verification. Codes outside 0..6 throw `std::out_of_range`, the deleting destructor throws, and STREAMS errnos absent from FreeBSD 11.4 [`errno.h`](https://github.com/freebsd/freebsd-src/blob/releng/11.4/sys/sys/errno.h) (`ENODATA`, `ENOSR`, `ENOSTR`, `ETIME`) are omitted. Codes 0..6 throw a 32-byte [VC12 `system_error`](https://github.com/ganboing/crt.vc12/blob/f1d47126/src/system_error) with FreeBSD errnos (16, 22, 3, 12, 1, 11, 35), a static `generic_category` (not `_Generic_object`), and unverified 40-byte [GuestLocale::String](../../../core/libs/prx/libc/include/GuestLocale.hpp) messages from [`syserror.cpp`](https://github.com/ganboing/crt.vc12/blob/f1d47126/src/syserror.cpp)
 - [Call tracing](../../../core/libs/prx/libc/src/specifics/x86_64/CallTrace.cpp) (`--trace-imports`, `APS5_TRACE_CALLS`) records only the entry of a call, not its arguments or result. One process-wide ring keeps the last 65536 calls, so a busy thread pushes the others out; the reporting thread's own calls are listed only while they are still in that ring. Calls are counted per traced target; an import bound to a target already traced under another name is counted under the first name. The thunk saves the integer argument registers and `xmm0` to `xmm7`; wider vector arguments survive only while the recording code avoids AVX, which is untested. Linux and macOS have no crash report, so they print the trace only on `SIGABRT` (guest or host `abort()`), not on `SIGSEGV`; a caller in a module loaded after the last traced import prints without a module name, and a thread aborting while another writes the report waits for it at most 2 seconds. An arm64 libc build omits the recorder
 - [_Dtest](../../../core/libs/prx/libc/src/Math.cpp) (libc) follows Dinkumware double classification matching _FDtest: finite values return -1, subnormals -2, zeros 0, infinities 1, and NaNs 2.