std.stdio.readln - multiple declarations

This version manages its own read buffer, which means one memory allocation per call. If you are not retaining a reference to the read data, consider the readln(buf) version, which may offer better performance as it can reuse its read buffer.

Prototype

S readln(S)(
  dchar terminator = '\x0a'
)
if (isSomeString!S);

Returns

The line that was read, including the line terminator character.

Parameters

Note

String terminators are not supported due to ambiguity with readln(buf) below.

Throws

StdioException on I/O error, or UnicodeException on Unicode conversion error.

Example

Reads stdin and writes it to stdout.

import std.stdio;

void main()
{
    string line;
    while ((line = readln()) !is null)
        write(line);
}

This can be faster than line = readln() because you can reuse the buffer for each call. Note that reusing the buffer means that you must copy the previous contents if you wish to retain them.

Prototypes

size_t readln(C)(
  C[] buf,
  dchar terminator = '\x0a'
)
if (isSomeChar!C && is(Unqual!C == C) && !is(C == enum));

size_t readln(C, R)(
  C[] buf,
  R terminator
)
if (isSomeChar!C && is(Unqual!C == C) && !is(C == enum) && isBidirectionalRange!R && is(typeof(terminator.front == (dchar).init)));

Returns

size_t 0 for end of file, otherwise number of characters read

Parameters

Throws

StdioException on I/O error, or UnicodeException on Unicode conversion error.

Example

Reads stdin and writes it to stdout.

import std.stdio;

void main()
{
    char[] buf;
    while (readln(buf))
        write(buf);
}