1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)printf.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd March 3, 2009 36.Dt PRINTF 3 37.Os 38.Sh NAME 39.Nm printf , fprintf , sprintf , snprintf , asprintf , dprintf , 40.Nm vprintf , vfprintf, vsprintf , vsnprintf , vasprintf, vdprintf 41.Nd formatted output conversion 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd "#define _WITH_DPRINTF" 46.In stdio.h 47.Ft int 48.Fn printf "const char * restrict format" ... 49.Ft int 50.Fn fprintf "FILE * restrict stream" "const char * restrict format" ... 51.Ft int 52.Fn sprintf "char * restrict str" "const char * restrict format" ... 53.Ft int 54.Fn snprintf "char * restrict str" "size_t size" "const char * restrict format" ... 55.Ft int 56.Fn asprintf "char **ret" "const char *format" ... 57.Ft int 58.Fn dprintf "int" "const char * restrict format" ... 59.In stdarg.h 60.Ft int 61.Fn vprintf "const char * restrict format" "va_list ap" 62.Ft int 63.Fn vfprintf "FILE * restrict stream" "const char * restrict format" "va_list ap" 64.Ft int 65.Fn vsprintf "char * restrict str" "const char * restrict format" "va_list ap" 66.Ft int 67.Fn vsnprintf "char * restrict str" "size_t size" "const char * restrict format" "va_list ap" 68.Ft int 69.Fn vasprintf "char **ret" "const char *format" "va_list ap" 70.Ft int 71.Fn vdprintf "int fd" "const char * restrict format" "va_list ap" 72.Sh DESCRIPTION 73The 74.Fn printf 75family of functions produces output according to a 76.Fa format 77as described below. 78The 79.Fn printf 80and 81.Fn vprintf 82functions 83write output to 84.Dv stdout , 85the standard output stream; 86.Fn fprintf 87and 88.Fn vfprintf 89write output to the given output 90.Fa stream ; 91.Fn dprintf 92and 93.Fn vdprintf 94write output to the given file descriptor; 95.Fn sprintf , 96.Fn snprintf , 97.Fn vsprintf , 98and 99.Fn vsnprintf 100write to the character string 101.Fa str ; 102and 103.Fn asprintf 104and 105.Fn vasprintf 106dynamically allocate a new string with 107.Xr malloc 3 . 108.Pp 109These functions write the output under the control of a 110.Fa format 111string that specifies how subsequent arguments 112(or arguments accessed via the variable-length argument facilities of 113.Xr stdarg 3 ) 114are converted for output. 115.Pp 116These functions return the number of characters printed 117(not including the trailing 118.Ql \e0 119used to end output to strings) or a negative value if an output error occurs, 120except for 121.Fn snprintf 122and 123.Fn vsnprintf , 124which return the number of characters that would have been printed if the 125.Fa size 126were unlimited 127(again, not including the final 128.Ql \e0 ) . 129.Pp 130The 131.Fn asprintf 132and 133.Fn vasprintf 134functions 135set 136.Fa *ret 137to be a pointer to a buffer sufficiently large to hold the formatted string. 138This pointer should be passed to 139.Xr free 3 140to release the allocated storage when it is no longer needed. 141If sufficient space cannot be allocated, 142.Fn asprintf 143and 144.Fn vasprintf 145will return \-1 and set 146.Fa ret 147to be a 148.Dv NULL 149pointer. 150.Pp 151The 152.Fn snprintf 153and 154.Fn vsnprintf 155functions 156will write at most 157.Fa size Ns \-1 158of the characters printed into the output string 159(the 160.Fa size Ns 'th 161character then gets the terminating 162.Ql \e0 ) ; 163if the return value is greater than or equal to the 164.Fa size 165argument, the string was too short 166and some of the printed characters were discarded. 167The output is always null-terminated. 168.Pp 169The 170.Fn sprintf 171and 172.Fn vsprintf 173functions 174effectively assume an infinite 175.Fa size . 176.Pp 177The format string is composed of zero or more directives: 178ordinary 179.\" multibyte 180characters (not 181.Cm % ) , 182which are copied unchanged to the output stream; 183and conversion specifications, each of which results 184in fetching zero or more subsequent arguments. 185Each conversion specification is introduced by 186the 187.Cm % 188character. 189The arguments must correspond properly (after type promotion) 190with the conversion specifier. 191After the 192.Cm % , 193the following appear in sequence: 194.Bl -bullet 195.It 196An optional field, consisting of a decimal digit string followed by a 197.Cm $ , 198specifying the next argument to access. 199If this field is not provided, the argument following the last 200argument accessed will be used. 201Arguments are numbered starting at 202.Cm 1 . 203If unaccessed arguments in the format string are interspersed with ones that 204are accessed the results will be indeterminate. 205.It 206Zero or more of the following flags: 207.Bl -tag -width ".So \ Sc (space)" 208.It Sq Cm # 209The value should be converted to an 210.Dq alternate form . 211For 212.Cm c , d , i , n , p , s , 213and 214.Cm u 215conversions, this option has no effect. 216For 217.Cm o 218conversions, the precision of the number is increased to force the first 219character of the output string to a zero. 220For 221.Cm x 222and 223.Cm X 224conversions, a non-zero result has the string 225.Ql 0x 226(or 227.Ql 0X 228for 229.Cm X 230conversions) prepended to it. 231For 232.Cm a , A , e , E , f , F , g , 233and 234.Cm G 235conversions, the result will always contain a decimal point, even if no 236digits follow it (normally, a decimal point appears in the results of 237those conversions only if a digit follows). 238For 239.Cm g 240and 241.Cm G 242conversions, trailing zeros are not removed from the result as they 243would otherwise be. 244.It So Cm 0 Sc (zero) 245Zero padding. 246For all conversions except 247.Cm n , 248the converted value is padded on the left with zeros rather than blanks. 249If a precision is given with a numeric conversion 250.Cm ( d , i , o , u , i , x , 251and 252.Cm X ) , 253the 254.Cm 0 255flag is ignored. 256.It Sq Cm \- 257A negative field width flag; 258the converted value is to be left adjusted on the field boundary. 259Except for 260.Cm n 261conversions, the converted value is padded on the right with blanks, 262rather than on the left with blanks or zeros. 263A 264.Cm \- 265overrides a 266.Cm 0 267if both are given. 268.It So "\ " Sc (space) 269A blank should be left before a positive number 270produced by a signed conversion 271.Cm ( a , A , d , e , E , f , F , g , G , 272or 273.Cm i ) . 274.It Sq Cm + 275A sign must always be placed before a 276number produced by a signed conversion. 277A 278.Cm + 279overrides a space if both are used. 280.It Sq Cm ' 281Decimal conversions 282.Cm ( d , u , 283or 284.Cm i ) 285or the integral portion of a floating point conversion 286.Cm ( f 287or 288.Cm F ) 289should be grouped and separated by thousands using 290the non-monetary separator returned by 291.Xr localeconv 3 . 292.El 293.It 294An optional decimal digit string specifying a minimum field width. 295If the converted value has fewer characters than the field width, it will 296be padded with spaces on the left (or right, if the left-adjustment 297flag has been given) to fill out 298the field width. 299.It 300An optional precision, in the form of a period 301.Cm \&. 302followed by an 303optional digit string. 304If the digit string is omitted, the precision is taken as zero. 305This gives the minimum number of digits to appear for 306.Cm d , i , o , u , x , 307and 308.Cm X 309conversions, the number of digits to appear after the decimal-point for 310.Cm a , A , e , E , f , 311and 312.Cm F 313conversions, the maximum number of significant digits for 314.Cm g 315and 316.Cm G 317conversions, or the maximum number of characters to be printed from a 318string for 319.Cm s 320conversions. 321.It 322An optional length modifier, that specifies the size of the argument. 323The following length modifiers are valid for the 324.Cm d , i , n , o , u , x , 325or 326.Cm X 327conversion: 328.Bl -column ".Cm q Em (deprecated)" ".Vt signed char" ".Vt unsigned long long" ".Vt long long *" 329.It Sy Modifier Ta Cm d , i Ta Cm o , u , x , X Ta Cm n 330.It Cm hh Ta Vt "signed char" Ta Vt "unsigned char" Ta Vt "signed char *" 331.It Cm h Ta Vt short Ta Vt "unsigned short" Ta Vt "short *" 332.It Cm l No (ell) Ta Vt long Ta Vt "unsigned long" Ta Vt "long *" 333.It Cm ll No (ell ell) Ta Vt "long long" Ta Vt "unsigned long long" Ta Vt "long long *" 334.It Cm j Ta Vt intmax_t Ta Vt uintmax_t Ta Vt "intmax_t *" 335.It Cm t Ta Vt ptrdiff_t Ta (see note) Ta Vt "ptrdiff_t *" 336.It Cm z Ta (see note) Ta Vt size_t Ta (see note) 337.It Cm q Em (deprecated) Ta Vt quad_t Ta Vt u_quad_t Ta Vt "quad_t *" 338.El 339.Pp 340Note: 341the 342.Cm t 343modifier, when applied to a 344.Cm o , u , x , 345or 346.Cm X 347conversion, indicates that the argument is of an unsigned type 348equivalent in size to a 349.Vt ptrdiff_t . 350The 351.Cm z 352modifier, when applied to a 353.Cm d 354or 355.Cm i 356conversion, indicates that the argument is of a signed type equivalent in 357size to a 358.Vt size_t . 359Similarly, when applied to an 360.Cm n 361conversion, it indicates that the argument is a pointer to a signed type 362equivalent in size to a 363.Vt size_t . 364.Pp 365The following length modifier is valid for the 366.Cm a , A , e , E , f , F , g , 367or 368.Cm G 369conversion: 370.Bl -column ".Sy Modifier" ".Cm a , A , e , E , f , F , g , G" 371.It Sy Modifier Ta Cm a , A , e , E , f , F , g , G 372.It Cm l No (ell) Ta Vt double 373(ignored, same behavior as without it) 374.It Cm L Ta Vt "long double" 375.El 376.Pp 377The following length modifier is valid for the 378.Cm c 379or 380.Cm s 381conversion: 382.Bl -column ".Sy Modifier" ".Vt wint_t" ".Vt wchar_t *" 383.It Sy Modifier Ta Cm c Ta Cm s 384.It Cm l No (ell) Ta Vt wint_t Ta Vt "wchar_t *" 385.El 386.It 387A character that specifies the type of conversion to be applied. 388.El 389.Pp 390A field width or precision, or both, may be indicated by 391an asterisk 392.Ql * 393or an asterisk followed by one or more decimal digits and a 394.Ql $ 395instead of a 396digit string. 397In this case, an 398.Vt int 399argument supplies the field width or precision. 400A negative field width is treated as a left adjustment flag followed by a 401positive field width; a negative precision is treated as though it were 402missing. 403If a single format directive mixes positional 404.Pq Li nn$ 405and non-positional arguments, the results are undefined. 406.Pp 407The conversion specifiers and their meanings are: 408.Bl -tag -width ".Cm diouxX" 409.It Cm diouxX 410The 411.Vt int 412(or appropriate variant) argument is converted to signed decimal 413.Cm ( d 414and 415.Cm i ) , 416unsigned octal 417.Pq Cm o , 418unsigned decimal 419.Pq Cm u , 420or unsigned hexadecimal 421.Cm ( x 422and 423.Cm X ) 424notation. 425The letters 426.Dq Li abcdef 427are used for 428.Cm x 429conversions; the letters 430.Dq Li ABCDEF 431are used for 432.Cm X 433conversions. 434The precision, if any, gives the minimum number of digits that must 435appear; if the converted value requires fewer digits, it is padded on 436the left with zeros. 437.It Cm DOU 438The 439.Vt "long int" 440argument is converted to signed decimal, unsigned octal, or unsigned 441decimal, as if the format had been 442.Cm ld , lo , 443or 444.Cm lu 445respectively. 446These conversion characters are deprecated, and will eventually disappear. 447.It Cm eE 448The 449.Vt double 450argument is rounded and converted in the style 451.Sm off 452.Oo \- Oc Ar d Li \&. Ar ddd Li e \\*[Pm] Ar dd 453.Sm on 454where there is one digit before the 455decimal-point character 456and the number of digits after it is equal to the precision; 457if the precision is missing, 458it is taken as 6; if the precision is 459zero, no decimal-point character appears. 460An 461.Cm E 462conversion uses the letter 463.Ql E 464(rather than 465.Ql e ) 466to introduce the exponent. 467The exponent always contains at least two digits; if the value is zero, 468the exponent is 00. 469.Pp 470For 471.Cm a , A , e , E , f , F , g , 472and 473.Cm G 474conversions, positive and negative infinity are represented as 475.Li inf 476and 477.Li -inf 478respectively when using the lowercase conversion character, and 479.Li INF 480and 481.Li -INF 482respectively when using the uppercase conversion character. 483Similarly, NaN is represented as 484.Li nan 485when using the lowercase conversion, and 486.Li NAN 487when using the uppercase conversion. 488.It Cm fF 489The 490.Vt double 491argument is rounded and converted to decimal notation in the style 492.Sm off 493.Oo \- Oc Ar ddd Li \&. Ar ddd , 494.Sm on 495where the number of digits after the decimal-point character 496is equal to the precision specification. 497If the precision is missing, it is taken as 6; if the precision is 498explicitly zero, no decimal-point character appears. 499If a decimal point appears, at least one digit appears before it. 500.It Cm gG 501The 502.Vt double 503argument is converted in style 504.Cm f 505or 506.Cm e 507(or 508.Cm F 509or 510.Cm E 511for 512.Cm G 513conversions). 514The precision specifies the number of significant digits. 515If the precision is missing, 6 digits are given; if the precision is zero, 516it is treated as 1. 517Style 518.Cm e 519is used if the exponent from its conversion is less than \-4 or greater than 520or equal to the precision. 521Trailing zeros are removed from the fractional part of the result; a 522decimal point appears only if it is followed by at least one digit. 523.It Cm aA 524The 525.Vt double 526argument is rounded and converted to hexadecimal notation in the style 527.Sm off 528.Oo \- Oc Li 0x Ar h Li \&. Ar hhhp Oo \\*[Pm] Oc Ar d , 529.Sm on 530where the number of digits after the hexadecimal-point character 531is equal to the precision specification. 532If the precision is missing, it is taken as enough to represent 533the floating-point number exactly, and no rounding occurs. 534If the precision is zero, no hexadecimal-point character appears. 535The 536.Cm p 537is a literal character 538.Ql p , 539and the exponent consists of a positive or negative sign 540followed by a decimal number representing an exponent of 2. 541The 542.Cm A 543conversion uses the prefix 544.Dq Li 0X 545(rather than 546.Dq Li 0x ) , 547the letters 548.Dq Li ABCDEF 549(rather than 550.Dq Li abcdef ) 551to represent the hex digits, and the letter 552.Ql P 553(rather than 554.Ql p ) 555to separate the mantissa and exponent. 556.Pp 557Note that there may be multiple valid ways to represent floating-point 558numbers in this hexadecimal format. 559For example, 560.Li 0x1.92p+1 , 0x3.24p+0 , 0x6.48p-1 , 561and 562.Li 0xc.9p-2 563are all equivalent. 564.Fx 8.0 565and later always prints finite non-zero numbers using 566.Ql 1 567as the digit before the hexadecimal point. 568Zeroes are always represented with a mantissa of 0 (preceded by a 569.Ql - 570if appropriate) and an exponent of 571.Li +0 . 572.It Cm C 573Treated as 574.Cm c 575with the 576.Cm l 577(ell) modifier. 578.It Cm c 579The 580.Vt int 581argument is converted to an 582.Vt "unsigned char" , 583and the resulting character is written. 584.Pp 585If the 586.Cm l 587(ell) modifier is used, the 588.Vt wint_t 589argument shall be converted to a 590.Vt wchar_t , 591and the (potentially multi-byte) sequence representing the 592single wide character is written, including any shift sequences. 593If a shift sequence is used, the shift state is also restored 594to the original state after the character. 595.It Cm S 596Treated as 597.Cm s 598with the 599.Cm l 600(ell) modifier. 601.It Cm s 602The 603.Vt "char *" 604argument is expected to be a pointer to an array of character type (pointer 605to a string). 606Characters from the array are written up to (but not including) 607a terminating 608.Dv NUL 609character; 610if a precision is specified, no more than the number specified are 611written. 612If a precision is given, no null character 613need be present; if the precision is not specified, or is greater than 614the size of the array, the array must contain a terminating 615.Dv NUL 616character. 617.Pp 618If the 619.Cm l 620(ell) modifier is used, the 621.Vt "wchar_t *" 622argument is expected to be a pointer to an array of wide characters 623(pointer to a wide string). 624For each wide character in the string, the (potentially multi-byte) 625sequence representing the 626wide character is written, including any shift sequences. 627If any shift sequence is used, the shift state is also restored 628to the original state after the string. 629Wide characters from the array are written up to (but not including) 630a terminating wide 631.Dv NUL 632character; 633if a precision is specified, no more than the number of bytes specified are 634written (including shift sequences). 635Partial characters are never written. 636If a precision is given, no null character 637need be present; if the precision is not specified, or is greater than 638the number of bytes required to render the multibyte representation of 639the string, the array must contain a terminating wide 640.Dv NUL 641character. 642.It Cm p 643The 644.Vt "void *" 645pointer argument is printed in hexadecimal (as if by 646.Ql %#x 647or 648.Ql %#lx ) . 649.It Cm n 650The number of characters written so far is stored into the 651integer indicated by the 652.Vt "int *" 653(or variant) pointer argument. 654No argument is converted. 655.It Cm % 656A 657.Ql % 658is written. 659No argument is converted. 660The complete conversion specification 661is 662.Ql %% . 663.El 664.Pp 665The decimal point 666character is defined in the program's locale (category 667.Dv LC_NUMERIC ) . 668.Pp 669In no case does a non-existent or small field width cause truncation of 670a numeric field; if the result of a conversion is wider than the field 671width, the 672field is expanded to contain the conversion result. 673.Sh EXAMPLES 674To print a date and time in the form 675.Dq Li "Sunday, July 3, 10:02" , 676where 677.Fa weekday 678and 679.Fa month 680are pointers to strings: 681.Bd -literal -offset indent 682#include <stdio.h> 683fprintf(stdout, "%s, %s %d, %.2d:%.2d\en", 684 weekday, month, day, hour, min); 685.Ed 686.Pp 687To print \*(Pi 688to five decimal places: 689.Bd -literal -offset indent 690#include <math.h> 691#include <stdio.h> 692fprintf(stdout, "pi = %.5f\en", 4 * atan(1.0)); 693.Ed 694.Pp 695To allocate a 128 byte string and print into it: 696.Bd -literal -offset indent 697#include <stdio.h> 698#include <stdlib.h> 699#include <stdarg.h> 700char *newfmt(const char *fmt, ...) 701{ 702 char *p; 703 va_list ap; 704 if ((p = malloc(128)) == NULL) 705 return (NULL); 706 va_start(ap, fmt); 707 (void) vsnprintf(p, 128, fmt, ap); 708 va_end(ap); 709 return (p); 710} 711.Ed 712.Sh SECURITY CONSIDERATIONS 713The 714.Fn sprintf 715and 716.Fn vsprintf 717functions are easily misused in a manner which enables malicious users 718to arbitrarily change a running program's functionality through 719a buffer overflow attack. 720Because 721.Fn sprintf 722and 723.Fn vsprintf 724assume an infinitely long string, 725callers must be careful not to overflow the actual space; 726this is often hard to assure. 727For safety, programmers should use the 728.Fn snprintf 729interface instead. 730For example: 731.Bd -literal 732void 733foo(const char *arbitrary_string, const char *and_another) 734{ 735 char onstack[8]; 736 737#ifdef BAD 738 /* 739 * This first sprintf is bad behavior. Do not use sprintf! 740 */ 741 sprintf(onstack, "%s, %s", arbitrary_string, and_another); 742#else 743 /* 744 * The following two lines demonstrate better use of 745 * snprintf(). 746 */ 747 snprintf(onstack, sizeof(onstack), "%s, %s", arbitrary_string, 748 and_another); 749#endif 750} 751.Ed 752.Pp 753The 754.Fn printf 755and 756.Fn sprintf 757family of functions are also easily misused in a manner 758allowing malicious users to arbitrarily change a running program's 759functionality by either causing the program 760to print potentially sensitive data 761.Dq "left on the stack" , 762or causing it to generate a memory fault or bus error 763by dereferencing an invalid pointer. 764.Pp 765.Cm %n 766can be used to write arbitrary data to potentially carefully-selected 767addresses. 768Programmers are therefore strongly advised to never pass untrusted strings 769as the 770.Fa format 771argument, as an attacker can put format specifiers in the string 772to mangle your stack, 773leading to a possible security hole. 774This holds true even if the string was built using a function like 775.Fn snprintf , 776as the resulting string may still contain user-supplied conversion specifiers 777for later interpolation by 778.Fn printf . 779.Pp 780Always use the proper secure idiom: 781.Pp 782.Dl "snprintf(buffer, sizeof(buffer), \*q%s\*q, string);" 783.Sh COMPATIBILITY 784Many application writers used the name 785.Va dprintf 786before the 787.Fn dprintf 788function was introduced in 789.St -p1003.1 , 790so a prototype is not provided by default in order to avoid 791compatibility problems. 792Applications that wish to use the 793.Fn dprintf 794function described herein should either request a strict 795.St -p1003.1-2008 796environment by defining the macro 797.Dv _POSIX_C_SOURCE 798to the value 200809 or greater, or by defining the macro 799.Dv _WITH_DPRINTF , 800prior to the inclusion of 801.In stdio.h . 802For compatibility with GNU libc, defining either 803.Dv _BSD_SOURCE 804or 805.Dv _GNU_SOURCE 806prior to the inclusion of 807.In stdio.h 808will also make 809.Fn dprintf 810available. 811.Pp 812The conversion formats 813.Cm \&%D , \&%O , 814and 815.Cm %U 816are not standard and 817are provided only for backward compatibility. 818The effect of padding the 819.Cm %p 820format with zeros (either by the 821.Cm 0 822flag or by specifying a precision), and the benign effect (i.e., none) 823of the 824.Cm # 825flag on 826.Cm %n 827and 828.Cm %p 829conversions, as well as other 830nonsensical combinations such as 831.Cm %Ld , 832are not standard; such combinations 833should be avoided. 834.Sh ERRORS 835In addition to the errors documented for the 836.Xr write 2 837system call, the 838.Fn printf 839family of functions may fail if: 840.Bl -tag -width Er 841.It Bq Er EILSEQ 842An invalid wide character code was encountered. 843.It Bq Er ENOMEM 844Insufficient storage space is available. 845.El 846.Sh SEE ALSO 847.Xr printf 1 , 848.Xr fmtcheck 3 , 849.Xr scanf 3 , 850.Xr setlocale 3 , 851.Xr wprintf 3 852.Sh STANDARDS 853Subject to the caveats noted in the 854.Sx BUGS 855section below, the 856.Fn fprintf , 857.Fn printf , 858.Fn sprintf , 859.Fn vprintf , 860.Fn vfprintf , 861and 862.Fn vsprintf 863functions 864conform to 865.St -ansiC 866and 867.St -isoC-99 . 868With the same reservation, the 869.Fn snprintf 870and 871.Fn vsnprintf 872functions conform to 873.St -isoC-99 , 874while 875.Fn dprintf 876and 877.Fn vdprintf 878conform to 879.St -p1003.1-2008 . 880.Sh HISTORY 881The functions 882.Fn asprintf 883and 884.Fn vasprintf 885first appeared in the 886.Tn GNU C 887library. 888These were implemented by 889.An Peter Wemm Aq peter@FreeBSD.org 890in 891.Fx 2.2 , 892but were later replaced with a different implementation 893from 894.An Todd C. Miller Aq Todd.Miller@courtesan.com 895for 896.Ox 2.3 . 897The 898.Fn dprintf 899and 900.Fn vdprintf 901functions were added in 902.Fx 8.0 . 903.Sh BUGS 904The 905.Nm 906family of functions do not correctly handle multibyte characters in the 907.Fa format 908argument. 909