Chr

The function chr returns the char which has ASCII value b. The signature reads:

function chr(b: byte): char;

The function is used and necessary because of Pascal's strong type safety. With the advent of typecasts a general method became available, though using chr is better style.

A trivial example shall demonstrate the usage of chr:

type
    // modern Latin alphabet has 26 letters
    latinAlphabetCharacterIndex = 0..25;

{$push}
// let compiler generate code ensuring n >= 0 and n < 26
{$rangeChecks on}
function getChrInLatinAlphabet(const n: latinAlphabetCharacterIndex): char;
begin
    getChrInLatinAlphabet := chr(ord('A') + n);
end;
{$pop}

FPC has implemented chr as a compiler intrinsic in_chr_byte.

see also

• chr in the system unit reference
• ord does the reverse operation.

From the Free Pascal wiki, page "Chr", as it stood on 2022-08-06 after a change by Kai Burghardt, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.