printf: formatting printing functions
type ('a, 'b, 'c) format
-
The type of format strings. 'a is the type of the parameters
of the string, 'c is the result type for the printf-style
function, and 'b is the type of the first argument given to
%a and %t printing functions.
value 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 one argument.
Conversion specifications consist in the % character, followed
by optional flags and field widths, followed by one conversion
character. The conversion characters and their meanings are:
d or i: convert an integer argument to signed decimal
u: convert an integer argument to unsigned decimal
x: convert an integer argument to unsigned hexadecimal,
using lowercase letters.
X: convert an integer argument to unsigned hexadecimal,
using uppercase letters.
s: insert a string argument
c: insert a character argument
f: convert a floating-point argument to decimal notation,
in the style dddd.ddd
e or E: convert a floating-point argument to decimal notation,
in the style d.ddd e+-dd (mantissa and exponent)
g or G: convert a floating-point argument to decimal notation,
in style f or e, E (whichever is more compact)
b: convert a boolean argument to the string true or false
a: user-defined printer. Takes two arguments and apply the first
one to outchan (the current output channel) and to the second
argument. The first argument must therefore have type
out_channel -> 'b -> unit and the second 'b.
The output produced by the function is therefore inserted
in the output of fprintf at the current point.
t: same as %a, but takes only one argument (with type
out_channel -> unit) and apply it to outchan.
Refer to the C library printf function for the meaning of
flags and field width specifiers.
If too few arguments are provided, printing stops just
before converting the first missing argument.
value printf: ('a, out_channel, unit) format -> 'a
-
Same as fprintf, but output on std_out.
value eprintf: ('a, out_channel, unit) format -> 'a
-
Same as fprintf, but output on std_err.
value sprintf: ('a, unit, string) format -> 'a
-
Same as fprintf, except that the result of the formatting
is returned as a string instead of being written on a channel.
value fprint: out_channel -> string -> unit
-
Print the given string on the given output channel, without
any formatting. This is the same function as output_string
of module io.
value print: string -> unit
-
Print the given string on std_out, without any formatting.
This is the same function as print_string of module io.
value eprint: string -> unit
-
Print the given string on std_err, without any formatting.
This is the same function as prerr_string of module io.