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use crate::io;
use crate::num::NonZeroUsize;
#[unstable(feature = "available_concurrency", issue = "74479")]
pub fn available_concurrency() -> io::Result<NonZeroUsize> {
available_concurrency_internal()
}
cfg_if::cfg_if! {
if #[cfg(windows)] {
#[allow(nonstandard_style)]
fn available_concurrency_internal() -> io::Result<NonZeroUsize> {
#[repr(C)]
struct SYSTEM_INFO {
wProcessorArchitecture: u16,
wReserved: u16,
dwPageSize: u32,
lpMinimumApplicationAddress: *mut u8,
lpMaximumApplicationAddress: *mut u8,
dwActiveProcessorMask: *mut u8,
dwNumberOfProcessors: u32,
dwProcessorType: u32,
dwAllocationGranularity: u32,
wProcessorLevel: u16,
wProcessorRevision: u16,
}
extern "system" {
fn GetSystemInfo(info: *mut SYSTEM_INFO) -> i32;
}
let res = unsafe {
let mut sysinfo = crate::mem::zeroed();
GetSystemInfo(&mut sysinfo);
sysinfo.dwNumberOfProcessors as usize
};
match res {
0 => Err(io::Error::new(io::ErrorKind::NotFound, "The number of hardware threads is not known for the target platform")),
cpus => Ok(unsafe { NonZeroUsize::new_unchecked(cpus) }),
}
}
} else if #[cfg(any(
target_os = "android",
target_os = "emscripten",
target_os = "fuchsia",
target_os = "ios",
target_os = "linux",
target_os = "macos",
target_os = "solaris",
target_os = "illumos",
))] {
fn available_concurrency_internal() -> io::Result<NonZeroUsize> {
match unsafe { libc::sysconf(libc::_SC_NPROCESSORS_ONLN) } {
-1 => Err(io::Error::last_os_error()),
0 => Err(io::Error::new(io::ErrorKind::NotFound, "The number of hardware threads is not known for the target platform")),
cpus => Ok(unsafe { NonZeroUsize::new_unchecked(cpus as usize) }),
}
}
} else if #[cfg(any(target_os = "freebsd", target_os = "dragonfly", target_os = "netbsd"))] {
fn available_concurrency_internal() -> io::Result<NonZeroUsize> {
use crate::ptr;
let mut cpus: libc::c_uint = 0;
let mut cpus_size = crate::mem::size_of_val(&cpus);
unsafe {
cpus = libc::sysconf(libc::_SC_NPROCESSORS_ONLN) as libc::c_uint;
}
if cpus < 1 {
let mut mib = [libc::CTL_HW, libc::HW_NCPU, 0, 0];
let res = unsafe {
libc::sysctl(
mib.as_mut_ptr(),
2,
&mut cpus as *mut _ as *mut _,
&mut cpus_size as *mut _ as *mut _,
ptr::null_mut(),
0,
)
};
if res == -1 {
return Err(io::Error::last_os_error());
} else if cpus == 0 {
return Err(io::Error::new(io::ErrorKind::NotFound, "The number of hardware threads is not known for the target platform"));
}
}
Ok(unsafe { NonZeroUsize::new_unchecked(cpus as usize) })
}
} else if #[cfg(target_os = "openbsd")] {
fn available_concurrency_internal() -> io::Result<NonZeroUsize> {
use crate::ptr;
let mut cpus: libc::c_uint = 0;
let mut cpus_size = crate::mem::size_of_val(&cpus);
let mut mib = [libc::CTL_HW, libc::HW_NCPU, 0, 0];
let res = unsafe {
libc::sysctl(
mib.as_mut_ptr(),
2,
&mut cpus as *mut _ as *mut _,
&mut cpus_size as *mut _ as *mut _,
ptr::null_mut(),
0,
)
};
if res == -1 {
return Err(io::Error::last_os_error());
} else if cpus == 0 {
return Err(io::Error::new(io::ErrorKind::NotFound, "The number of hardware threads is not known for the target platform"));
}
Ok(unsafe { NonZeroUsize::new_unchecked(cpus as usize) })
}
} else {
fn available_concurrency_internal() -> io::Result<NonZeroUsize> {
Err(io::Error::new(io::ErrorKind::NotFound, "The number of hardware threads is not known for the target platform"))
}
}
}