HPUX sprintf[3s]
printf(3S) printf(3S)
NAME
printf(), nl_printf(), fprintf(), nl_fprintf(), sprintf(),
nl_sprintf() - print formatted output
SYNOPSIS
#include <stdio.h>
int printf(const char *format, /* [arg,] */ ...);
int nl_printf(const char *format, /* [arg,] */ ...);
int fprintf(FILE *stream, const char *format, /* [arg,] */ ...);
int nl_fprintf(FILE *stream, const char *format, /* [arg,] */ ...);
int sprintf(char *s, const char *format, /* [arg,] */ ...);
int nl_sprintf(char *s, const char *format, /* [arg,] */ ...);
DESCRIPTION
printf() and nl_printf() place output on the standard output stream
stdout.
fprintf() and nl_fprintf() place output on the named output stream.
sprintf() and nl_sprintf() place ``output'', followed by the null
character (\0), in consecutive bytes starting at *s. It is the user's
responsibility to ensure that enough storage is available.
Each function converts, formats, and prints its args under control of
the format. format is a character string containing two types of
objects: plain characters that are copied to the output stream, and
conversion specifications, each of which results in fetching zero or
more args. The results are undefined if there are insufficient args
for the format. If the format is exhausted while args remain, excess
args are ignored.
Each conversion specification is introduced by the character % or %n$,
where n is a decimal integer in the range 1 through {NL_ARGMAX}
(NL_ARGMAX is defined in <limits.h>). The %n$ construction indicates
that this conversion should be applied to the nth argument, rather
than to the next unused one.
An argument can be referenced by a %n$ specification more than once.
The two forms of introducing a conversion specification, % and %n$,
cannot be mixed within a single format string. Improper use of %n$ in
a format string results in a negative return value.
After the % or %n$, the following appear in sequence:
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1. Zero or more flags, which modify the meaning of the
conversion specification.
2. An optional string of decimal digits to specify a minimum
field width in bytes. If the converted value has fewer
characters than the field width, it is be padded on the left
(or right, if the left-adjustment flag (-), described below,
has been given) to the field width. If the field width is
preceded by a zero, the string is right adjusted with zero-
padding on the left (see the leading-zero flag (0) described
below).
3. A precision that gives the minimum number of digits to
appear for the d, i, o, u, x, or X conversions, the number
of digits to appear after the radix character for the e and
f conversions, the maximum number of significant digits for
the g conversion, or the maximum number of bytes to be
printed from a string in the s conversion. The precision
takes the form of a period (.) followed by a decimal digit
string; a null digit string is treated as zero.
4. An optional l (the letter ``ell''), specifying that a
following d, i, o, u, x, or X conversion character applies
to a long integer arg; an optional l specifying that a
following n conversion character applies to a pointer to a
long integer arg; an optional h, specifying that a following
d, i, o, u, x, or X conversion character applies to a short
integer arg; an optional h specifying that a following n
conversion character applies to a pointer to a short integer
arg; an optional L specifying that a following e, E, f, g,
or G conversion character applies to a long double arg. An
l, h or L before any other conversion character is ignored.
5. A conversion character that indicates the type of conversion
to be applied.
A field width or precision can be indicated by an asterisk (*) instead
of a digit string. In this case, an integer arg supplies the field
width or precision. The arg that is actually converted is not fetched
until the conversion letter is seen, so the args specifying field
width, or precision, or both must appear in that order before the arg,
if any, to be converted. A negative field width is taken as a - flag
followed by a positive field width. A negative precision is taken as
if the precision were omitted. Format strings containing %n$
conversion specifications can also indicate a field width or precision
by the sequence *n$. The n indicates the position of an integer arg.
With the *n$ sequence, the args specifying field width or precision
can appear before or after the arg to be converted.
The flag characters and their meanings are:
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- The resulting conversion is left-justified within the
field.
+ The resulting signed conversion always begins with a
sign (+ or -).
blank If the first character of a signed conversion is not a
sign, a blank is prefixed to the result. This implies
that if the blank and + flags both appear, the blank
flag is ignored.
# This flag specifies that the value is converted to an
``alternateform''. For c, d, i, s, n, and u
conversions, the flag has no effect. For o conversion,
it increases the precision to force the first digit of
the result to be a zero. For x or X conversion, a
non-zero result has 0x or 0X prefixed to it. For a p
conversion, a non-zero result has 0x prefixed to it.
For e, E, f, g, and G conversions, the result always
contains a radix character, even if no digits follow
the radix (normally, a radix character appears in the
resulting conversions only if followed by a digit).
For g and G conversions, trailing zeroes are not
removed from the result (which they normally are).
0 Leading zeros (following any indication of sign or
base) are used to pad to the field width for all
conversion characters. No space padding is performed.
If both the 0 and - appear, the 0 flag is ignored. For
d, i, o, u, p, x, and X, conversions, if a precision is
specified, the 0 flag is ignored.
The conversion characters and their meanings are:
d,i,o,u,x,X The integer arg is converted to signed decimal (d
and i are identical), unsigned octal (o), decimal
(u), or hexadecimal notation (x and X),
respectively; the letters abcdef are used for x
conversion and the letters ABCDEF for X
conversion. The precision specifies the minimum
number of digits to appear; if the value being
converted can be represented in fewer digits, it
is expanded with leading zeroes. (For
compatibility with older versions, padding with
leading zeroes can alternatively be specified by
inserting a zero in front of the field width.
This does not imply an octal value for the field
width.) The default precision is 1. The result of
converting a zero value with a precision of zero
is a null string.
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f The double arg is converted to decimal notation in
the style [-]dddrddd, where r is the radix
character. The number of digits after the radix
character is equal to the precision specification.
If the precision is missing, six digits are
output. If the precision is explicitly zero, no
radix character appears.
e,E The double arg is converted in the style [-
]drddde_ddd, where r is the radix character.
There is one digit before the radix character and
the number of digits after it is equal to the
precision; when the precision is missing, six
digits are produced; if the precision is zero, no
radix character appears. The E format code
produces a number with E instead of e introducing
the exponent. The exponent always contains at
least two digits.
g,G The double arg is printed in style f or e (or in
style E in the case of a G format code), with the
precision specifying the number of significant
digits. The style used depends on the value
converted: style e is used only if the exponent
resulting from the conversion is less than -4 or
greater than or equal to the precision. Trailing
zeroes are removed from the fractional part of the
result; a radix character appears only if it is
followed by a digit.
c The int arg is converted to an unsigned char, and
the resulting character is printed.
C The wchar_t arg is converted to an array of bytes
representing the single wide character according
to the setting of LC_CTYPE. Resulting bytes are
printed. If the precision is given, it is
ignored. If the field width would otherwise cause
the wide character to be split, the wide character
is printed and the field width is adjusted upward.
s The arg is taken to be a string (character
pointer) and characters from the string are
printed until a null character (\0) is encountered
or the number of bytes indicated by the precision
specification is reached. If the precision is
missing, it is taken to be infinite, so all
characters up to the first null character are
printed. A NULL value for arg yields undefined
results.
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S The arg is taken to be a pointer to a wide
character string (wchar_t *). Wide characters
from the string are converted to an array of bytes
representing the string of wide characters
according to the setting of LC_CTYPE. Resulting
bytes are printed until a null wide character
((wchar_t)0) is encountered or the number of bytes
indicated by the precision is reached. If the
precision is missing, it is taken to be infinite,
so all wide characters up to the first null wide
character are printed. If the field width would
otherwise cause the last multibyte character to be
split, the last wide character is not printed. A
NULL value for arg yields undefined results.
p The value of a pointer to void arg is printed as a
sequence of unsigned hexadecimal numbers. The
precision specifies the minimum number of digits
to appear; if the value being converted can be
represented in fewer digits, it is expanded with
leading zeroes. The default precision is 1. The
result of converting a zero value with a precision
of zero is a null string.
n A pointer to an integer arg is expected. This
pointer is used to store the number of bytes
printed on the output stream so far by this call
to the function. No argument is converted.
% Print a %; no argument is converted.
In no case does a nonexistent or small field width cause truncation of
a field; if the result of a conversion is wider than the field width,
the field is expanded to contain the conversion result.
Characters generated by printf(), fprintf(), nl_printf(), and
nl_fprintf() are printed as if putc() had been called (see putc(3S)).
EXTERNAL INFLUENCES
Locale
The LC_CTYPE category affects the following features:
o Plain characters within format strings are interpreted as
single and/or multi-byte characters.
o Field width is given in terms of bytes. As characters are
placed on the output stream, they are interpreted as single or
multi-byte characters and the field width is decremented by
the length of the character.
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o Precision is given in terms of bytes. As characters are
placed on the output stream, they are interpreted as single or
multi-byte characters and the precision is decremented by the
length of the character.
o The return value is given in terms of bytes. As characters
are placed on the output stream, they are interpreted as
single or multi-byte characters and the byte count that makes
up the return value is incremented by the length of the
character.
The LC_NUMERIC category determines the radix character used to print
floating-point numbers.
International Code Set Support
Single-byte character code sets are supported. Multi-byte character
code sets are also supported as described in the LC_CTYPE category
above.
RETURN VALUE
Each function returns the number of bytes transmitted (excluding the
\0 in the case of sprintf() and nl_sprintf()), or a negative value if
an output error was encountered. Improper use of %n$ in a format
string results in a negative return value.
ERRORS
printf(), fprintf(), nl_printf(), and nl_fprintf() fail if either the
stream is unbuffered or stream's buffer needed to be flushed causing
an underlying write() call to be invoked (see write(2)), and:
[EAGAIN] The O_NONBLOCK flag is set for the file descriptor
underlying stream and the process would be delayed
in the write operation.
[EBADF] The file descriptor underlying stream is not a
valid file descriptor open for writing.
[EFBIG] An attempt was made to write to a file that
exceeds the process's file size limit or the
maximum file size (see ulimit(2)).
[EINTR] A signal was caught during the write() system
call.
[EIO] The process is in a background process group and
is attempting to write to its controlling
terminal, TOSTOP is set, the process is neither
ignoring nor blocking the SIGTTOU signal, and the
process group of the process is orphaned.
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[ENOSPC] There was no free space remaining on the device
containing the file.
[EPIPE] An attempt is made to write to a pipe or FIFO that
is not open for reading by any process. A SIGPIPE
signal is also sent to the process.
Additional errno values can be set by the underlying write() function
(see write(2)).
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, %d:%.2d", weekday, month, day, hour, min);
To print pi to 5 decimal places:
printf("pi = %.5f", 4 * atan(1.0));
To create a language-independent date-and-time printing routine write:
printf(format,weekday,month,day,hour,min,2,2);
For American usage, format would point to the string:
"%1$s, %2$s %3$d, %4$*6$.*7$d:%5$*6$.*7$d"
and result in the output:
"Sunday, July 3, 10:02"
For German usage, the string:
"%1$s, %3$s %2$d, %4$*6$.*7$d:%5$*6$.*7$d"
results in the output:
Sonntag, 3 Juli 10:02
WARNINGS
nl_printf(), nl_fprintf(), and nl_sprintf() are provided for
historical reasons only. Their use is not recommended. Use printf(),
fprintf(), and sprintf() instead.
Notice that with the c conversion character, an int arg is converted
to an unsigned char. Hence, whole multi-byte characters cannot be
printed using a single c conversion character.
A precision with the s conversion character might result in the
truncation of a multi-byte character.
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AUTHOR
printf(), fprintf(), and sprintf() were developed by AT&T and HP.
nl_printf(), nl_fprintf(), and nl_sprintf() were developed by HP.
SEE ALSO
ecvt(3C), setlocale(3C), putc(3S), scanf(3S), stdio(3S).
STANDARDS CONFORMANCE
printf(): AES, SVID2, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C
fprintf(): AES, SVID2, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C
nl_fprintf(): XPG2
nl_printf(): XPG2
nl_sprintf(): XPG2
sprintf(): AES, SVID2, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C
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