# 2.11BSD#431 - /usr/man/cat1/printf.0

    PRINTF(1)	    UNIX Programmer's Manual		PRINTF(1)

    NAME
         printf - formatted output

    SYNOPSIS
         printf format [ arguments ... ]

    DESCRIPTION
         Printf formats and prints its arguments, after the first,
         under control of the format.  The format is a character
         string which contains three types of objects: plain charac-
         ters, which are simply copied to standard output, character
         escape sequences which are converted and copied to the stan-
         dard output, and format specifications, each of which causes
         printing of the next successive argument.

         The arguments after the first are treated as strings if the
         corresponding format is either c or s; otherwise it is
         evaluated as a C constant, with the following extensions:

         o+	  A leading plus or minus sign is allowed.

         o+	  If the leading character is a single or double quote,
    	  or not a digit, plus, or minus sign, the value is the
    	  ASCII code of the next character.

         The format string is reused as often as necessary to satisfy
         the arguments.  Any extra format specifications are
         evaluated with zero or the null string.

         Character escape sequences are in backslash notation as
         defined in the draft proposed ANSI C Standard X3J11.  The
         characters and their meanings are as follows:

    	  \a	    Write a <bell> character.

    	  \b	    Write a <backspace> character.

    	  \f	    Write a <form-feed> character.

    	  \n	    Write a <new-line> character.

    	  \r	    Write a <carriage return> character.

    	  \t	    Write a <tab> character.

    	  \v	    Write a <vertical tab> character.

    	  \'	    Write a <single quote> character.

    	  \\	    Write a backslash character.

    	  \num	    Write an 8-bit character whose ASCII value is the

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         PRINTF(1)		 UNIX Programmer's Manual	     PRINTF(1)

    		    1-, 2-, or 3-digit octal number num.

         Each format specification is introduced by the percent char-
         acter (``%'').  The remainder of the format specification
         includes, in the following order:

         "Zero or more of the following flags:"

    	  #	    A `#' character specifying that the value should
    		    be printed in an ``alternate form''.  For c, d,
    		    and s, formats, this option has no effect.	For
    		    the o formats the precision of the number is
    		    increased to force the first character of the out-
    		    put string to a zero.  For the x (X) format, a
    		    non-zero result has the string 0x (0X) prepended
    		    to it.  For e, E, f, g, and G, formats, the result
    		    will always contain a decimal point, even if no
    		    digits follow the point (normally, a decimal point
    		    only appears in the results of those formats if a
    		    digit follows the decimal point).  For g and G
    		    formats, trailing zeros are not removed from the
    		    result as they would otherwise be;

    	  -	    A minus sign `-' which specifies left adjustment
    		    of the output in the indicated field;

    	  +	    A `+' character specifying that there should
    		    always be a sign placed before the number when
    		    using signed formats.

    	  ` '	    A space specifying that a blank should be left
    		    before a positive number for a signed format.  A
    		    `+' overrides a space if both are used;

    	  0	    A zero `0' character indicating that zero-padding
    		    should be used rather than blank-padding.  A `-'
    	       overrides a `0' if both are used;

         Field Width:
    	       An optional digit string specifying a field width;
    	       if the output string has fewer characters than the
    	       field width it will be blank-padded on the left
    	       (or right, if the left-adjustment indicator has
    	       been given) to make up the field width (note that
    	       a leading zero is a flag, but an embedded zero is
    	       part of a field width);

         Precision:
    	       An optional period, followed by an optional digit
    	       string giving a precision which specifies the
    	       number of digits to appear after the decimal

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    PRINTF(1)	    UNIX Programmer's Manual		PRINTF(1)

    	       point, for e and f formats, or the maximum number
    	       of characters to be printed from a string; if the
    	       digit string is missing, the precision is treated
    	       as zero;

         Format:
    	       A character which indicates the type of format to
    	       use (one of diouxXfwEgGcs).

         A field width or precision may be * instead of a digit
         string.  In this case an argument supplies the field width
         or precision.

         The format characters and their meanings are:

         diouXx    The argument is printed as a signed decimal (d or
    	       i), unsigned decimal, unsigned octal, or unsigned
    	       hexadecimal (X or x), respectively.

         f	       The argument is printed in the style `[-]ddd.ddd'
    	       where the number of d's after the decimal point is
    	       equal to the precision specification for the argu-
    	       ment.  If the precision is missing, 6 digits are
    	       given; if the precision is explicitly 0, no digits
    	       and no decimal point are printed.

         eE        The argument is printed in the style e where there
    	       is one digit before the decimal point and the
    	       number after is equal to the precision specifica-
    	       tion for the argument; when the precision is miss-
    	       ing, 6 digits are produced.  An upper-case E is
    	       used for an `E' format.

         gG        The argument is printed in style f or in style e
    	       (E) whichever gives full precision in minimum
    	       space.

         c	       The first character of argument is printed.

         s	       Characters from the string argument are printed
    	       until the end is reached or until the number of
    	       characters indicated by the precision specifica-
    	       tion is reached; however if the precision is 0 or
    	       missing, all characters in the string are printed.

         %	       Print a `%'; no argument is used.

         In no case does a non-existent or small field width cause
         truncation of a field; padding takes place only if the
         specified field width exceeds the actual width.

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    PRINTF(1)	    UNIX Programmer's Manual		PRINTF(1)

    RETURN VALUES
         Printf exits 0 on success, 1 on failure.

    SEE ALSO
         printf(3)

    HISTORY
         The printf command appeared in 4.3-Reno.  It is modeled
         after the standard library function, printf(3).

    BUGS
         Since the floating point numbers are translated from ASCII
         to floating-point and then back again, floating-point preci-
         sion may be lost.

         ANSI hexadecimal character constants were deliberately not
         provided.

    Printed 11/26/99	   May 2, 1995				4

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