Zig 0.17.0-dev (Split by item)

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lockMemory

Request part of the calling process's virtual address space to be in RAM, preventing that memory from being paged to the swap area.

Corresponds to "mlock" or "mlock2" in libc.

File

lib/std/process.zig:962

Code

pub fn lockMemory(memory: []align(std.heap.page_size_min) const u8, options: LockMemoryOptions) LockMemoryError!void {
    if (native_os == .windows) {
        // TODO call VirtualLock
    }
    if (!options.on_fault and @TypeOf(posix.system.mlock) != void) {
        switch (posix.errno(posix.system.mlock(memory.ptr, memory.len))) {
            .SUCCESS => return,
            .INVAL => |err| return std.Io.Threaded.errnoBug(err), // unaligned, negative, runs off end of addrspace
            .PERM => return error.PermissionDenied,
            .NOMEM => return error.LockedMemoryLimitExceeded,
            .AGAIN => return error.SystemResources,
            else => |err| return posix.unexpectedErrno(err),
        }
    }
    if (@TypeOf(posix.system.mlock2) != void) {
        const flags: posix.MLOCK = .{ .ONFAULT = options.on_fault };
        switch (posix.errno(posix.system.mlock2(memory.ptr, memory.len, flags))) {
            .SUCCESS => return,
            .INVAL => |err| return std.Io.Threaded.errnoBug(err), // unaligned, negative, runs off end of addrspace
            .PERM => return error.PermissionDenied,
            .NOMEM => return error.LockedMemoryLimitExceeded,
            .AGAIN => return error.SystemResources,
            else => |err| return posix.unexpectedErrno(err),
        }
    }
    return error.UnsupportedOperation;
}