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4 .\" This code is derived from software contributed to Berkeley by
5 .\" Chris Torek and the American National Standards Committee X3,
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32 .\" @(#)printf.3 8.1 (Berkeley) 6/4/93
33 .\" FreeBSD: src/lib/libc/stdio/printf.3,v 1.47 2002/09/06 11:23:55 tjr Exp
34 .\" $FreeBSD: src/lib/libc/stdio/wprintf.3,v 1.6 2007/01/09 00:28:08 imp Exp $
35 .\" $DragonFly: src/lib/libc/stdio/wprintf.3,v 1.3 2007/11/04 16:23:23 swildner Exp $
47 .Nd formatted wide character output conversion
54 .Fn fwprintf "FILE * restrict stream" "const wchar_t * restrict format" ...
56 .Fn swprintf "wchar_t * restrict ws" "size_t n" "const wchar_t * restrict format" ...
58 .Fn wprintf "const wchar_t * restrict format" ...
61 .Fn vfwprintf "FILE * restrict stream" "const wchar_t * restrict" "va_list ap"
63 .Fn vswprintf "wchar_t * restrict ws" "size_t n" "const wchar_t *restrict format" "va_list ap"
65 .Fn vwprintf "const wchar_t * restrict format" "va_list ap"
69 family of functions produces output according to a
79 the standard output stream;
83 write output to the given output
88 write to the wide character string
91 These functions write the output under the control of a
93 string that specifies how subsequent arguments
94 (or arguments accessed via the variable-length argument facilities of
96 are converted for output.
98 These functions return the number of characters printed
99 (not including the trailing
101 used to end output to strings).
107 functions will fail if
109 or more wide characters were requested to be written,
111 The format string is composed of zero or more directives:
115 which are copied unchanged to the output stream;
116 and conversion specifications, each of which results
117 in fetching zero or more subsequent arguments.
118 Each conversion specification is introduced by
122 The arguments must correspond properly (after type promotion)
123 with the conversion specifier.
126 the following appear in sequence:
129 An optional field, consisting of a decimal digit string followed by a
131 specifying the next argument to access.
132 If this field is not provided, the argument following the last
133 argument accessed will be used.
134 Arguments are numbered starting at
136 If unaccessed arguments in the format string are interspersed with ones that
137 are accessed the results will be indeterminate.
139 Zero or more of the following flags:
140 .Bl -tag -width ".So \ Sc (space)"
142 The value should be converted to an
145 .Cm c , d , i , n , p , s ,
148 conversions, this option has no effect.
151 conversions, the precision of the number is increased to force the first
152 character of the output string to a zero (except if a zero value is printed
153 with an explicit precision of zero).
158 conversions, a non-zero result has the string
164 conversions) prepended to it.
166 .Cm a , A , e , E , f , F , g ,
169 conversions, the result will always contain a decimal point, even if no
170 digits follow it (normally, a decimal point appears in the results of
171 those conversions only if a digit follows).
176 conversions, trailing zeros are not removed from the result as they
178 .It So Cm 0 Sc (zero)
180 For all conversions except
182 the converted value is padded on the left with zeros rather than blanks.
183 If a precision is given with a numeric conversion
184 .Cm ( d , i , o , u , i , x ,
191 A negative field width flag;
192 the converted value is to be left adjusted on the field boundary.
195 conversions, the converted value is padded on the right with blanks,
196 rather than on the left with blanks or zeros.
202 .It So "\ " Sc (space)
203 A blank should be left before a positive number
204 produced by a signed conversion
205 .Cm ( a , A , d , e , E , f , F , g , G ,
209 A sign must always be placed before a
210 number produced by a signed conversion.
213 overrides a space if both are used.
219 or the integral portion of a floating point conversion
223 should be grouped and separated by thousands using
224 the non-monetary separator returned by
228 An optional decimal digit string specifying a minimum field width.
229 If the converted value has fewer characters than the field width, it will
230 be padded with spaces on the left (or right, if the left-adjustment
231 flag has been given) to fill out
234 An optional precision, in the form of a period
237 optional digit string.
238 If the digit string is omitted, the precision is taken as zero.
239 This gives the minimum number of digits to appear for
240 .Cm d , i , o , u , x ,
243 conversions, the number of digits to appear after the decimal-point for
244 .Cm a , A , e , E , f ,
247 conversions, the maximum number of significant digits for
251 conversions, or the maximum number of characters to be printed from a
256 An optional length modifier, that specifies the size of the argument.
257 The following length modifiers are valid for the
258 .Cm d , i , n , o , u , x ,
262 .Bl -column ".Cm q Em (deprecated)" ".Vt signed char" ".Vt unsigned long long" ".Vt long long *"
263 .It Sy Modifier Ta Cm d , i Ta Cm o , u , x , X Ta Cm n
264 .It Cm hh Ta Vt "signed char" Ta Vt "unsigned char" Ta Vt "signed char *"
265 .It Cm h Ta Vt short Ta Vt "unsigned short" Ta Vt "short *"
266 .It Cm l No (ell) Ta Vt long Ta Vt "unsigned long" Ta Vt "long *"
267 .It Cm ll No (ell ell) Ta Vt "long long" Ta Vt "unsigned long long" Ta Vt "long long *"
268 .It Cm j Ta Vt intmax_t Ta Vt uintmax_t Ta Vt "intmax_t *"
269 .It Cm t Ta Vt ptrdiff_t Ta (see note) Ta Vt "ptrdiff_t *"
270 .It Cm z Ta (see note) Ta Vt size_t Ta (see note)
271 .It Cm q Em (deprecated) Ta Vt quad_t Ta Vt u_quad_t Ta Vt "quad_t *"
277 modifier, when applied to a
281 conversion, indicates that the argument is of an unsigned type
282 equivalent in size to a
286 modifier, when applied to a
290 conversion, indicates that the argument is of a signed type equivalent in
293 Similarly, when applied to an
295 conversion, it indicates that the argument is a pointer to a signed type
296 equivalent in size to a
299 The following length modifier is valid for the
300 .Cm a , A , e , E , f , F , g ,
304 .Bl -column ".Sy Modifier" ".Cm a , A , e , E , f , F , g , G"
305 .It Sy Modifier Ta Cm a , A , e , E , f , F , g , G
306 .It Cm L Ta Vt "long double"
309 The following length modifier is valid for the
314 .Bl -column ".Sy Modifier" ".Vt wint_t" ".Vt wchar_t *"
315 .It Sy Modifier Ta Cm c Ta Cm s
316 .It Cm l No (ell) Ta Vt wint_t Ta Vt "wchar_t *"
319 A character that specifies the type of conversion to be applied.
322 A field width or precision, or both, may be indicated by
325 or an asterisk followed by one or more decimal digits and a
331 argument supplies the field width or precision.
332 A negative field width is treated as a left adjustment flag followed by a
333 positive field width; a negative precision is treated as though it were
335 If a single format directive mixes positional
337 and non-positional arguments, the results are undefined.
339 The conversion specifiers and their meanings are:
340 .Bl -tag -width ".Cm diouxX"
344 (or appropriate variant) argument is converted to signed decimal
352 or unsigned hexadecimal
361 conversions; the letters
366 The precision, if any, gives the minimum number of digits that must
367 appear; if the converted value requires fewer digits, it is padded on
372 argument is converted to signed decimal, unsigned octal, or unsigned
373 decimal, as if the format had been
378 These conversion characters are deprecated, and will eventually disappear.
382 argument is rounded and converted in the style
384 .Oo \- Oc Ar d Li \&. Ar ddd Li e \\*[Pm] Ar dd
386 where there is one digit before the
387 decimal-point character
388 and the number of digits after it is equal to the precision;
389 if the precision is missing,
390 it is taken as 6; if the precision is
391 zero, no decimal-point character appears.
394 conversion uses the letter
398 to introduce the exponent.
399 The exponent always contains at least two digits; if the value is zero,
403 .Cm a , A , e , E , f , F , g ,
406 conversions, positive and negative infinity are represented as
410 respectively when using the lowercase conversion character, and
414 respectively when using the uppercase conversion character.
415 Similarly, NaN is represented as
417 when using the lowercase conversion, and
419 when using the uppercase conversion.
423 argument is rounded and converted to decimal notation in the style
425 .Oo \- Oc Ar ddd Li \&. Ar ddd ,
427 where the number of digits after the decimal-point character
428 is equal to the precision specification.
429 If the precision is missing, it is taken as 6; if the precision is
430 explicitly zero, no decimal-point character appears.
431 If a decimal point appears, at least one digit appears before it.
435 argument is converted in style
446 The precision specifies the number of significant digits.
447 If the precision is missing, 6 digits are given; if the precision is zero,
451 is used if the exponent from its conversion is less than \-4 or greater than
452 or equal to the precision.
453 Trailing zeros are removed from the fractional part of the result; a
454 decimal point appears only if it is followed by at least one digit.
458 argument is converted to hexadecimal notation in the style
460 .Oo \- Oc Li 0x Ar h Li \&. Ar hhhp Oo \\*[Pm] Oc Ar d ,
462 where the number of digits after the hexadecimal-point character
463 is equal to the precision specification.
464 If the precision is missing, it is taken as enough to exactly
465 represent the floating-point number; if the precision is
466 explicitly zero, no hexadecimal-point character appears.
467 This is an exact conversion of the mantissa+exponent internal
468 floating point representation; the
470 .Oo \- Oc Li 0x Ar h Li \&. Ar hhh
472 portion represents exactly the mantissa; only denormalized
473 mantissas have a zero value to the left of the hexadecimal
477 is a literal character
479 the exponent is preceded by a positive or negative sign
480 and is represented in decimal, using only enough characters
481 to represent the exponent.
484 conversion uses the prefix
492 to represent the hex digits, and the letter
496 to separate the mantissa and exponent.
506 argument is converted to an
507 .Vt "unsigned char" ,
512 and the resulting character is written.
516 (ell) modifier is used, the
518 argument is converted to a
530 argument is expected to be a pointer to an array of character type (pointer
531 to a string) containing a multibyte sequence.
532 Characters from the array are converted to wide characters and written up to
537 if a precision is specified, no more than the number specified are
539 If a precision is given, no null character
540 need be present; if the precision is not specified, or is greater than
541 the size of the array, the array must contain a terminating
547 (ell) modifier is used, the
549 argument is expected to be a pointer to an array of wide characters
550 (pointer to a wide string).
551 Each wide character in the string
553 Wide characters from the array are written up to (but not including)
557 if a precision is specified, no more than the number specified are
558 written (including shift sequences).
559 If a precision is given, no null character
560 need be present; if the precision is not specified, or is greater than
561 the number of characters in
562 the string, the array must contain a terminating wide
568 pointer argument is printed in hexadecimal (as if by
573 The number of characters written so far is stored into the
574 integer indicated by the
576 (or variant) pointer argument.
577 No argument is converted.
582 No argument is converted.
583 The complete conversion specification
589 character is defined in the program's locale (category
592 In no case does a non-existent or small field width cause truncation of
593 a numeric field; if the result of a conversion is wider than the field
595 field is expanded to contain the conversion result.
596 .Sh SECURITY CONSIDERATIONS
608 Subject to the caveats noted in the