Module Printf


module Printf: sig .. end
Formatted output functions.

val fprintf : out_channel ->
('a, out_channel, unit) format -> 'a
fprintf outchan format arg1 ... argN formats the arguments arg1 to argN according to the format string format, and outputs the resulting string on the channel outchan.

The format is a character string which contains two types of objects: plain characters, which are simply copied to the output channel, and conversion specifications, each of which causes conversion and printing of arguments.

Conversion specifications have the following form:

% [positional specifier] [flags] [width] [.precision] type

In short, a conversion specification consists in the % character, followed by optional modifiers and a type which is made of one or two characters. The types and their meanings are:

The optional positional specifier consists of an integer followed by a $; the integer indicates which argument to use, the first argument being denoted by 1.

The optional flags are:

The optional width is an integer indicating the minimal width of the result. For instance, %6d prints an integer, prefixing it with spaces to fill at least 6 characters.

The optional precision is a dot . followed by an integer indicating how many digits follow the decimal point in the %f, %e, and %E conversions. For instance, %.4f prints a float with 4 fractional digits.

The integer in a width or precision can also be specified as *, in which case an extra integer argument is taken to specify the corresponding width or precision. This integer argument precedes immediately the argument to print, unless an optional positional specifier is given to indicates which argument to use. For instance, %.*3$f prints a float with as many fractional digits as the value of the third argument.

val printf : ('a, out_channel, unit) format -> 'a
Same as Printf.fprintf, but output on stdout.
val eprintf : ('a, out_channel, unit) format -> 'a
Same as Printf.fprintf, but output on stderr.
val ifprintf : 'a -> ('b, 'a, unit) format -> 'b
Same as Printf.fprintf, but does not print anything. Useful to ignore some material when conditionally printing.
val sprintf : ('a, unit, string) format -> 'a
Same as Printf.fprintf, but instead of printing on an output channel, return a string containing the result of formatting the arguments.
val bprintf : Buffer.t -> ('a, Buffer.t, unit) format -> 'a
Same as Printf.fprintf, but instead of printing on an output channel, append the formatted arguments to the given extensible buffer (see module Buffer).
val kfprintf : (out_channel -> 'a) ->
out_channel ->
('b, out_channel, unit, 'a) format4 -> 'b
Formatted output functions with continuations.

Same as fprintf, but instead of returning immediately, passes the out channel to its first argument at the end of printing.

val ksprintf : (string -> 'a) -> ('b, unit, string, 'a) format4 -> 'b
Same as sprintf above, but instead of returning the string, passes it to the first argument.
val kbprintf : (Buffer.t -> 'a) ->
Buffer.t -> ('b, Buffer.t, unit, 'a) format4 -> 'b
Same as bprintf, but instead of returning immediately, passes the buffer to its first argument at the end of printing.
val kprintf : (string -> 'a) -> ('b, unit, string, 'a) format4 -> 'b
A deprecated synonym for ksprintf.