NAME

       Printf - Formatted output functions.

Module

       Module   Printf

Documentation

       Module Printf
        : sig end

       Formatted output functions.

       val    fprintf    :   Pervasives.out_channel   ->   ('a,   Pervasives.out_channel,   unit)
       Pervasives.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  string  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:

       % [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:

       - d , i : convert an integer argument to signed decimal.

       - u , n , l , L , or N : convert an integer argument to unsigned decimal.  Warning: n ,  l
       , L , and N are used for scanf , and should not be used for printf .

       - x : convert an integer argument to unsigned hexadecimal, using lowercase letters.

       - X : convert an integer argument to unsigned hexadecimal, using uppercase letters.

       - o : convert an integer argument to unsigned octal.

       - s : insert a string argument.

       - S : convert a string argument to OCaml syntax (double quotes, escapes).

       - c : insert a character argument.

       - C : convert a character argument to OCaml syntax (single quotes, escapes).

       - f : convert a floating-point argument to decimal notation, in the style dddd.ddd .

       -  F  :  convert  a  floating-point argument to OCaml syntax ( dddd.  or dddd.ddd or d.ddd
       e+-dd ).

       - 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).

       - h or H : convert a  floating-point  argument  to  hexadecimal  notation,  in  the  style
       0xh.hhhh e+-dd (hexadecimal mantissa, exponent in decimal and denotes a power of 2).

       - B : convert a boolean argument to the string true or false

       - b : convert a boolean argument (deprecated; do not use in new programs).

       -  ld  , li , lu , lx , lX , lo : convert an int32 argument to the format specified by the
       second letter (decimal, hexadecimal, etc).

       - nd , ni , nu , nx , nX , no : convert a nativeint argument to the  format  specified  by
       the second letter.

       -  Ld  , Li , Lu , Lx , LX , Lo : convert an int64 argument to the format specified by the
       second letter.

       - a : user-defined printer. Take 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
       inserted in the output of fprintf at the current point.

       -  t  : same as %a , but take only one argument (with type out_channel -> unit ) and apply
       it to outchan .

       - { fmt %} : convert a format string argument to its type digest.  The argument must  have
       the same type as the internal format string fmt .

       -  (  fmt %) : format string substitution. Take a format string argument and substitute it
       to the internal format string fmt to print following arguments. The argument must have the
       same type as the internal format string fmt .

       - !  : take no argument and flush the output.

       - % : take no argument and output one % character.

       - @ : take no argument and output one @ character.

       -   ,   :  take  no  argument  and  output  nothing:  a  no-op  delimiter  for  conversion
       specifications.

       The optional flags are:

       - - : left-justify the output (default is right justification).

       - 0 : for numerical conversions, pad with zeroes instead of spaces.

       - + : for signed numerical conversions, prefix number with a + sign if positive.

       -space: for signed numerical conversions, prefix number with a space if positive.

       - # : request an alternate formatting style for the hexadecimal and octal integer types  (
       x , X , o , lx , lX , lo , Lx , LX , Lo ).

       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.  For instance, %.*f  prints  a  float
       with as many fractional digits as the value of the argument given before the float.

       val printf : ('a, Pervasives.out_channel, unit) Pervasives.format -> 'a

       Same as Printf.fprintf , but output on stdout .

       val eprintf : ('a, Pervasives.out_channel, unit) Pervasives.format -> 'a

       Same as Printf.fprintf , but output on stderr .

       val sprintf : ('a, unit, string) Pervasives.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) Pervasives.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 ifprintf : 'b -> ('a, 'b, 'c, unit) Pervasives.format4 -> 'a

       Same as Printf.fprintf , but does not print anything.  Useful to ignore some material when
       conditionally printing.

       Since 3.10.0

       === Formatted output functions with continuations. ===

       val  kfprintf  :  (Pervasives.out_channel  ->  'd)  ->  Pervasives.out_channel   ->   ('a,
       Pervasives.out_channel, unit, 'd) Pervasives.format4 -> 'a

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

       Since 3.09.0

       val ikfprintf : ('b -> 'd) -> 'b -> ('a, 'b, 'c, 'd) Pervasives.format4 -> 'a

       Same as kfprintf above, but does not print anything.  Useful to ignore some material  when
       conditionally printing.

       Since 4.01.0

       val ksprintf : (string -> 'd) -> ('a, unit, string, 'd) Pervasives.format4 -> 'a

       Same  as  sprintf  above,  but  instead  of  returning  the string, passes it to the first
       argument.

       Since 3.09.0

       val kbprintf : (Buffer.t -> 'd) -> Buffer.t -> ('a, Buffer.t, unit, 'd) Pervasives.format4
       -> 'a

       Same  as  bprintf  ,  but instead of returning immediately, passes the buffer to its first
       argument at the end of printing.

       Since 3.10.0

       === Deprecated ===

       val kprintf : (string -> 'b) -> ('a, unit, string, 'b) Pervasives.format4 -> 'a

       A deprecated synonym for ksprintf .