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This is an example of documentation generated by ZigDoc, an alternative to Zig's built-in Auto Doc feature. See also examples in other modes/formats. The project being documented here (as the example) is the Zig standard library. Private Function

fillUnbuffered

Doc Source

Private Function

std.Io.Reader.fillUnbuffered

fn fillUnbuffered(r: *Reader, n: usize) Error!void

This internal function is separated from fill to encourage optimizers to inline fill, hence propagating its @branchHint to usage sites. If these functions are combined, fill is large enough that LLVM is reluctant to inline it, forcing usages of APIs like takeInt to go through an expensive runtime function call just to figure out that the data is, in fact, already in the buffer.

Missing this optimization can result in wall-clock time for the most affected benchmarks increasing by a factor of 5 or more.

Params

r: *Reader
n: usize

Errors

ReadFailed: See the Reader implementation for detailed diagnostics.
EndOfStream

File

Io/Reader.zig:1125

fn fillUnbuffered(r: *Reader, n: usize) Error!void {
    try rebase(r, n);
    var bufs: [1][]u8 = .{""};
    while (r.end < r.seek + n) _ = try r.vtable.readVec(r, &bufs);
}