PRINTF(3S)																PRINTF(3S)

NAME

       printf, fprintf, sprintf, vfprintf, vsprintf - formatted output conversion

SYNOPSIS

       #include <stdio.h>

       char *printf(format [, arg ] ...  )
       char *format;

       char *fprintf(stream, format [, arg ] ...  )
       FILE *stream;
       char *format;

       int sprintf(s, format [, arg ] ...  )
       char *s, *format;

       #include <varargs.h>
       char *vprintf(format, args)
       char *format;
       va_list args;

       char *vfprintf(stream, format, args)
       FILE *stream;
       char *format;
       va_list args;

       int vsprintf(s, format, args)
       char *s, *format;
       va_list args;

DESCRIPTION

       Printf  places  output on the standard output stream stdout.  Fprintf places output on the named output stream.	Sprintf places `output' in
       the string s, followed by the character `'.  Alternate forms, in which the arguments have already been captured using the variable-length
       argument facilities of varargs(3), are available under the names vprintf, vfprintf, and vsprintf.

       Each  of  these functions converts, formats, and prints its arguments after the first under control of the first argument.  The first argu-
       ment is a character string which contains two types of objects: plain characters, which are simply copied to the output stream, and conver-
       sion specifications, each of which causes conversion and printing of the next successive arg printf.

       Each  conversion  specification	is introduced by the character %.  The remainder of the conversion specification includes in the following
       order

       o      a minus sign `-' which specifies left adjustment of the converted value in the indicated field;

       o      an optional digit string specifying a field width; if the converted value 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; if the field width
	      begins with a zero, zero-padding will be done instead of blank-padding;

       o      an optional period, followed by an optional digit string giving a precision which specifies the number of digits to appear after the
	      decimal point, for e- and f-conversion, or the maximum number of characters to be printed from a string;

       o      the character l specifying that a following d, o, x, or u corresponds to a long integer arg;

       o      a character which indicates the type of conversion to be applied.

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

       The conversion characters and their meanings are

       dox    The integer arg is converted to signed decimal, unsigned octal, or unsigned hexadecimal notation respectively.

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

       e      The  float  or double arg is converted in the style `[-]d.ddde+-dd' where there is one digit before the decimal point and the number
	      after is equal to the precision specification for the argument; when the precision is missing, 6 digits are produced.

       g      The float or double arg is printed in style d, in style f, or in style e, whichever gives full precision in minimum space.

       c      The character arg is printed.

       s      Arg is taken to be a string (character pointer) and characters from the string are printed until a null character or until the  num-
	      ber of characters indicated by the precision specification is reached; however if the precision is 0 or missing all characters up to
	      a null are printed.

       u      The unsigned integer arg is converted to decimal and printed (the result will be in the  range  0  through  MAXUINT,  where  MAXUINT
	      equals 4294967295 on a VAX-11 and 65535 on a PDP-11).

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

       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.  Characters generated by printf are printed as by putc(3S).

RETURN VALUE

       The functions all return the number of characters printed, or -1 if an error occurred.

EXAMPLES

       To print a date and time in the form `Sunday, July 3, 10:02', where weekday and month are pointers to null-terminated strings:

	      printf("%s, %s %d, %02d:%02d", weekday, month, day, hour, min);

       To print pi to 5 decimals:

	      printf("pi = %.5f", 4*atan(1.0));

SEE ALSO

       putc(3S), scanf(3S)

BUGS

       Very wide fields (>300 characters) fail.

       Only sprintf and vsprintf return a count of characters transferred.

       The functions still supports %D, %O, %U and %X.	Do not use these formats, as they will be disappearing real soon now.

7th Edition							  August 10, 1988							PRINTF(3S)