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enable_extended_FILE_stdio(3C)
posix_spawnattr_getschedparam(3C)
posix_spawnattr_getschedpolicy(3C)
posix_spawnattr_getsigdefault(3C)
posix_spawnattr_getsigignore_np(3C)
posix_spawnattr_getsigmask(3C)
posix_spawnattr_setschedparam(3C)
posix_spawnattr_setschedpolicy(3C)
posix_spawnattr_setsigdefault(3C)
posix_spawnattr_setsigignore_np(3C)
posix_spawnattr_setsigmask(3C)
posix_spawn_file_actions_addclose(3C)
posix_spawn_file_actions_addclosefrom_np(3C)
posix_spawn_file_actions_adddup2(3C)
posix_spawn_file_actions_addopen(3C)
posix_spawn_file_actions_destroy(3C)
posix_spawn_file_actions_init(3C)
pthread_attr_getdetachstate(3C)
pthread_attr_getinheritsched(3C)
pthread_attr_getschedparam(3C)
pthread_attr_getschedpolicy(3C)
pthread_attr_setdetachstate(3C)
pthread_attr_setinheritsched(3C)
pthread_attr_setschedparam(3C)
pthread_attr_setschedpolicy(3C)
pthread_barrierattr_destroy(3C)
pthread_barrierattr_getpshared(3C)
pthread_barrierattr_setpshared(3C)
pthread_condattr_getpshared(3C)
pthread_condattr_setpshared(3C)
pthread_cond_reltimedwait_np(3C)
pthread_key_create_once_np(3C)
pthread_mutexattr_getprioceiling(3C)
pthread_mutexattr_getprotocol(3C)
pthread_mutexattr_getpshared(3C)
pthread_mutexattr_getrobust(3C)
pthread_mutexattr_setprioceiling(3C)
pthread_mutexattr_setprotocol(3C)
pthread_mutexattr_setpshared(3C)
pthread_mutexattr_setrobust(3C)
pthread_mutex_getprioceiling(3C)
pthread_mutex_reltimedlock_np(3C)
pthread_mutex_setprioceiling(3C)
pthread_rwlockattr_destroy(3C)
pthread_rwlockattr_getpshared(3C)
pthread_rwlockattr_setpshared(3C)
pthread_rwlock_reltimedrdlock_np(3C)
pthread_rwlock_reltimedwrlock_np(3C)
pthread_rwlock_timedrdlock(3C)
pthread_rwlock_timedwrlock(3C)
rctlblk_get_enforced_value(3C)
- print formatted output
#include <stdio.h>intprintf(const char *restrictformat,/*args*/ ...);
intfprintf(FILE *restrictstream,const char *restrictformat,/*args*/ ...);
intsprintf(char *restricts,const char *restrictformat,/*args*/ ...);
intsnprintf(char *restricts,size_tn,const char *restrictformat,/*args*/ ...);
intasprintf(char **ret,const char *restrictformat,/*args*/ ...);
Theprintf() function places output on the standard output streamstdout.
Thefprintf() function places output on on the named output streamstream.
Thesprintf() function places output, followed by the null byte (\0), inconsecutive bytes starting ats; it is the user's responsibility to ensurethat enough storage is available.
Thesnprintf() function is identical tosprintf() with the addition of theargumentn, which specifies the size of the buffer referred to bys. Ifn is 0, nothing is written ands can bea null pointer. Otherwise, output bytes beyond then-1st are discarded insteadof being written to the array and a null byte is writtenat the end of the bytes actually written into the array.
Theasprintf() function is the same as thesprintf() function except thatit returns, in theret argument, a pointer to a buffer sufficientlylarge to hold the output string. This pointer should be passed tofree(3C) to release the allocated storage when it is no longer needed.If sufficient space cannot be allocated, theasprintf() function returns -1 andsetsret to be aNULL pointer.
Each of these functions converts, formats, and prints its arguments under controlof theformat. Theformat is a character string, beginning and endingin its initial shift state, if any. Theformat is composed ofzero or more directives:ordinary characters, which are simply copied to the output streamandconversion specifications, each of which results in the fetching of zero ormore arguments. The results are undefined if there are insufficient arguments fortheformat. If theformat is exhausted while arguments remain, the excessarguments are evaluated but are otherwise ignored.
Conversions can be applied to thenth argument after theformat inthe argument list, rather than to the next unused argument. In thiscase, the conversion specifier% (see below) is replaced by the sequence%n$, wheren is a decimal integer in the range [1,NL_ARGMAX],giving the position of the argument in the argument list. This featureprovides for the definition of format strings that select arguments in anorder appropriate to specific languages (see theEXAMPLES section).
In format strings containing the%n$ form of conversion specifications, numbered argumentsin the argument list can be referenced from the format string asmany times as required.
In format strings containing the% form of conversion specifications, each argumentin the argument list is used exactly once.
All forms of theprintf() functions allow for the insertion of alanguage-dependent radix character in the output string. The radix character is definedby the program's locale (categoryLC_NUMERIC). In the POSIX locale, or ina locale where the radix character is not defined, the radix character defaultsto a period (.).
Each conversion specification is introduced by the% character or by thecharacter sequence%n$, after which the following appear in sequence:
An optional field, consisting of a decimal digit string followed by a$, specifying the next argument to be converted. If this field is not provided, theargs following the last argument converted will be used.
Zero or moreflags (in any order), which modify the meaning of the conversion specification.
An optional minimumfield width. If the converted value has fewer bytes than the field width, it will be padded with spaces by default on the left; it will be padded on the right, if the left-adjustment flag (-), described below, is given to the field width. The field width takes the form of an asterisk (*), described below, or a decimal integer.
If the conversion specifier iss, a standard-conforming application (seestandards(5)) interprets the field width as the minimum number of bytes to be printed; an application that is not standard-conforming interprets the field width as the minimum number of columns of screen display. For an application that is not standard-conforming,%10s means if the converted value has a screen width of 7 columns, 3 spaces would be padded on the right.
If the format is%ws, then the field width should be interpreted as the minimum number of columns of screen display.
An optionalprecision that gives the minimum number of digits to appear for thed,i,o,u,x, andX conversions (the field is padded with leading zeros); the number of digits to appear after the radix character for thea,A,e,E,f, andF conversions, the maximum number of significant digits for theg andG conversions; or the maximum number of bytes to be printed from a string ins andS conversions. The precision takes the form of a period (.) followed either by an asterisk (*), described below, or an optional decimal digit string, where a null digit string is treated as 0. If a precision appears with any other conversion specifier, the behavior is undefined.
If the conversion specifier iss orS, a standard-conforming application (seestandards(5)) interprets the precision as the maximum number of bytes to be written; an application that is not standard-conforming interprets the precision as the maximum number of columns of screen display. For an application that is not standard-conforming,%.5s would print only the portion of the string that would display in 5 screen columns. Only complete characters are written.
For%ws, the precision should be interpreted as the maximum number of columns of screen display. The precision takes the form of a period (.) followed by a decimal digit string; a null digit string is treated as zero. Padding specified by the precision overrides the padding specified by the field width.
An optionallength modifier that specified the size of the argument.
Aconversion specifier that indicates the type of conversion to be applied.
A field width, or precision, or both can be indicated by anasterisk (*) . In this case, an argument of typeint suppliesthe field width or precision. Arguments specifying field width, or precision, orboth must appear in that order before the argument, if any, to beconverted. A negative field width is taken as a - flag followedby a positive field width. A negative precision is taken as ifthe precision were omitted. In format strings containing the%n$ form ofa conversion specification, a field width or precision may be indicated by thesequence*m$, wherem is a decimal integer in the range [1,NL_ARGMAX] giving the position in the argument list (after the format argument) ofan integer argument containing the field width or precision, for example:
printf("%1$d:%2$.*3$d:%4$.*3$d\n", hour, min, precision, sec);Theformat can contain either numbered argument specifications (that is,%n$ and*m$), or unnumbered argument specifications (that is,% and*), but normallynot both. The only exception to this is that%% can bemixed with the%n$ form. The results of mixing numbered and unnumberedargument specifications in aformat string are undefined. When numbered argument specifications areused, specifying theNth argument requires that all the leading arguments, fromthe first to the (N–1)th, are specified in the format string.
The flag characters and their meanings are:
The integer portion of the result of a decimal conversion (%i,%d,%u,%f,%F,%g, or%G) will be formatted with thousands' grouping characters. For other conversions the behavior is undefined. The non-monetary grouping character is used.
The result of the conversion will be left-justified within the field. The conversion will be right-justified if this flag is not specified.
The result of a signed conversion will always begin with a sign (+ or –). The conversion will begin with a sign only when a negative value is converted if this flag is not specified.
If the first character of a signed conversion is not a sign or if a signed conversion results in no characters, a space will be placed before the result. This means that if thespace and+ flags both appear, the space flag will be ignored.
The value is to be converted to an alternate form. Forc,d,i,s, andu conversions, the flag has no effect. For ano conversion, it increases the precision (if necessary) to force the first digit of the result to be a zero. Forx orX conversion, a non-zero result will have0x (or0X) prepended to it. Fora,A,e,E,f,F,g, andG conversions, the result will always contain a radix character, even if no digits follow the radix character. Without this flag, the radix character appears in the result of these conversions only if a digit follows it. Forg andG conversions, trailing zeros will not be removed from the result as they normally are.
Ford,i,o,u,x,X,a,A,e,E,f,F,g, andG conversions, leading zeros (following any indication of sign or base) are used to pad to the field width; no space padding is performed. If the0 and- flags both appear, the0 flag will be ignored. Ford,i,o,u,x, andX conversions, if a precision is specified, the0 flag will be ignored. If the0 and' flags both appear, the grouping characters are inserted before zero padding. For other conversions, the behavior is undefined.
The length modifiers and their meanings are:
Specifies that a followingd,i,o,u,x, orX conversion specifier applies to asigned char orunsigned char argument (the argument will have been promoted according to the integer promotions, but its value will be converted tosigned char orunsigned char before printing); or that a followingn conversion specifier applies to a pointer to asigned char argument.
Specifies that a followingd,i,o,u,x, orX conversion specifier applies to ashort orunsigned short argument (the argument will have been promoted according to the integer promotions, but its value will be converted toshort orunsigned short before printing); or that a followingn conversion specifier applies to a pointer to ashort argument.
Specifies that a followingd,i,o,u,x, orX conversion specifier applies to along orunsigned long argument; that a followingn conversion specifier applies to a pointer to along argument; that a followingc conversion specifier applies to awint_t argument; that a followings conversion specifier applies to a pointer to awchar_t argument; or has no effect on a followinga,A,e,E,f,F,g, orG conversion specifier.
Specifies that a followingd,i,o,u,x, orX conversion specifier applies to along long orunsigned long long argument; or that a followingn conversion specifier applies to a pointer to along long argument.
Specifies that a followingd,i,o,u,x, orX conversion specifier applies to anintmax_t oruintmax_t argument; or that a followingn conversion specifier applies to a pointer to anintmax_t argument. See NOTES.
Specifies that a followingd,i,o,u,x, orX conversion specifier applies to asize_t or the corresponding signed integer type argument; or that a followingn conversion specifier applies to a pointer to a signed integer type corresponding tosize_t argument.
Specifies that a followingd,i,o,u,x, orX conversion specifier applies to aptrdiff_t or the corresponding unsigned type argument; or that a following n conversion specifier applies to a pointer to aptrdiff_t argument.
Specifies that a followinga,A,e,E,f,F,g, orG conversion specifier applies to along double argument.
If a length modifier appears with any conversion specifier other than asspecified above, the behavior is undefined.
Each conversion specifier results in fetching zero or more arguments. The resultsare undefined if there are insufficient arguments for the format. If theformat is exhausted while arguments remain, the excess arguments are ignored.
The conversion specifiers and their meanings are:
Theint argument is converted to a signed decimal in the style[-]dddd. The precision specifies the minimum number of digits to appear; if the value being converted can be represented in fewer digits, it will be expanded with leading zeros. The default precision is 1. The result of converting 0 with an explicit precision of 0 is no characters.
Theunsigned int argument is converted to unsigned octal format in the styledddd. The precision specifies the minimum number of digits to appear; if the value being converted can be represented in fewer digits, it will be expanded with leading zeros. The default precision is 1. The result of converting 0 with an explicit precision of 0 is no characters.
Theunsigned int argument is converted to unsigned decimal format in the styledddd. The precision specifies the minimum number of digits to appear; if the value being converted can be represented in fewer digits, it will be expanded with leading zeros. The default precision is 1. The result of converting 0 with an explicit precision of 0 is no characters.
Theunsigned int argument is converted to unsigned hexadecimal format in the styledddd; the lettersabcdef are used. The precision specifies the minimum number of digits to appear; if the value being converted can be represented in fewer digits, it will be expanded with leading zeros. The default precision is 1. The result of converting 0 with an explicit precision of 0 is no characters.
Behaves the same as thex conversion specifier except that lettersABCDEF are used instead ofabcdef.
Thedouble argument is converted to decimal notation in the style [-]ddd.ddd, where the number of digits after the radix character (seesetlocale(3C)) is equal to the precision specification. If the precision is missing it is taken as 6; if the precision is explicitly 0 and the# flag is not specified, no radix character appears. If a radix character appears, at least 1 digit appears before it. The converted value is rounded to fit the specified output format according to the prevailing floating point rounding direction mode. If the conversion is not exact, an inexact exception is raised.
For thef specifier, a double argument representing an infinity or NaN is converted in the style of thee conversion specifier, except that for an infinite argument, “infinity” or “Infinity” is printed when the precision is at least 8 and “inf” or “Inf” is printed otherwise.
For the F specifier, a double argument representing an infinity or NaN is converted in the SUSv3 style of the E conversion specifier, except that for an infinite argument, “INFINITY” is printed when the precision is at least 8 and or “INF” is printed otherwise.
Thedouble argument is converted to the style [-]d.ddde±dd, where there is one digit before the radix character (which is non-zero if the argument is non-zero) and the number of digits after it is equal to the precision. When the precision is missing it is taken as 6; if the precision is 0 and the# flag is not specified, no radix character appears. TheE conversion specifier will produce a number withE instead ofe introducing the exponent. The exponent always contains at least two digits. The converted value is rounded to fit the specified output format according to the prevailing floating point rounding direction mode. If the conversion is not exact, an inexact exception is raised.
Infinity and NaN values are handled in one of the following ways:
For thee specifier, adouble argument representing an infinity is printed as “[-]infinity”, when the precision for the conversion is at least 7 and as “[-]inf” otherwise. Adouble argument representing a NaN is printed as “[-]nan”. For theE specifier, “INF”, “INFINITY”, and “NAN” are printed instead of “inf”, “infinity”, and “nan”, respectively. Printing of the sign follows the rules described above.
Adouble argument representing an infinity is printed as “[-]Infinity”, when the precision for the conversion is at least 7 and as “[-]Inf” otherwise. A double argument representing a NaN is printed as “[-]NaN”. Printing of the sign follows the rules described above.
Thedouble argument is printed in stylef ore (or in styleE in the case of aG conversion specifier), with the precision specifying the number of significant digits. If an explicit precision is 0, it is taken as 1. The style used depends on the value converted: stylee (orE) will be used only if the exponent resulting from the conversion is less than –4 or greater than or equal to the precision. Trailing zeros are removed from the fractional part of the result. A radix character appears only if it is followed by a digit.
Adouble argument representing an infinity or NaN is converted in the style of thee orE conversion specifier, except that for an infinite argument, “infinity”, “INFINITY”, or “Infinity” is printed when the precision is at least 8 and “inf”, “INF”, or “Inf” is printed otherwise.
Adouble argument representing a floating-point number is converted in the style “[-]0xh.hhhhp±d”, where the single hexadecimal digit preceding the radix point is 0 if the value converted is zero and 1 otherwise and the number of hexadecimal digits after it is equal to the precision; if the precision is missing, the number of digits printed after the radix point is 13 for the conversion of a double value, 16 for the conversion of a long double value on x86, and 28 for the conversion of a long double value on SPARC; if the precision is zero and the '#' flag is not specified, no decimal-point character will appear. The letters “abcdef” are used fora conversion and the letters “ABCDEF” forA conversion. TheA conversion specifier produces a number with 'X' and 'P' instead of 'x' and 'p'. The exponent will always contain at least one digit, and only as many more digits as necessary to represent the decimal exponent of 2. If the value is zero, the exponent is zero.
The converted value is rounded to fit the specified output format according to the prevailing floating point rounding direction mode. If the conversion is not exact, an inexact exception is raised.
Adouble argument representing an infinity or NaN is converted in the SUSv3 style of ane orE conversion specifier.
Theint argument is converted to anunsigned char, and the resulting byte is printed.
If anl (ell) qualifier is present, thewint_t argument is converted as if by anls conversion specification with no precision and an argument that points to a two-element array of typewchar_t, the first element of which contains thewint_t argument to thels conversion specification and the second element contains a null wide-character.
Same aslc.
Theint argument is converted to a wide character (wchar_t), and the resulting wide character is printed.
The argument must be a pointer to an array ofchar. Bytes from the array are written up to (but not including) any terminating null byte. If a precision is specified, a standard-conforming application (seestandards(5)) will write only the number of bytes specified by precision; an application that is not standard-conforming will write only the portion of the string that will display in the number of columns of screen display specified by precision. If the precision is not specified, it is taken to be infinite, so all bytes up to the first null byte are printed. An argument with a null value will yield undefined results.
If anl (ell) qualifier is present, the argument must be a pointer to an array of typewchar_t. Wide-characters from the array are converted to characters (each as if by a call to thewcrtomb(3C) function, with the conversion state described by anmbstate_t object initialized to zero before the first wide-character is converted) up to and including a terminating null wide-character. The resulting characters are written up to (but not including) the terminating null character (byte). If no precision is specified, the array must contain a null wide-character. If a precision is specified, no more than that many characters (bytes) are written (including shift sequences, if any), and the array must contain a null wide-character if, to equal the character sequence length given by the precision, the function would need to access a wide-character one past the end of the array. In no case is a partial character written.
Same asls.
The argument must be a pointer to an array ofwchar_t. Bytes from the array are written up to (but not including) any terminating null character. If the precision is specified, only that portion of the wide-character array that will display in the number of columns of screen display specified by precision will be written. If the precision is not specified, it is taken to be infinite, so all wide characters up to the first null character are printed. An argument with a null value will yield undefined results.
The argument must be a pointer tovoid. The value of the pointer is converted to a set of sequences of printable characters, which should be the same as the set of sequences that are matched by the%p conversion of thescanf(3C) function.
The argument must be a pointer to an integer into which is written the number of bytes written to the output standard I/O stream so far by this call to one of theprintf() functions. No argument is converted.
Print a%; no argument is converted. The entire conversion specification must be %%.
If a conversion specification does not match one of the above forms,the behavior is undefined.
In no case does a non-existent or small field width cause truncationof a field; if the result of a conversion is wider thanthe field width, the field is simply expanded to contain the conversionresult. Characters generated byprintf() andfprintf() are printed as if theputc(3C)function had been called.
Thest_ctime andst_mtime fields of the file will be marked forupdate between the call to a successful execution ofprintf() orfprintf()and the next successful completion of a call tofflush(3C) orfclose(3C)on the same stream or a call toexit(3C) orabort(3C).
Theprintf(),fprintf(),sprintf(), andasprintf() functions return the number of bytestransmitted (excluding the terminating null byte in the case ofsprintf() andasprintf()).
Thesnprintf() function returns the number of bytes that would have beenwritten tos ifn had been sufficiently large (excluding the terminatingnull byte.) If the value ofn is 0 on a calltosnprintf(),s can be a null pointer and the number ofbytes that would have been written ifn had been sufficiently large(excluding the terminating null byte) is returned.
Each function returns a negative value if an output error was encountered.
For the conditions under whichprintf() andfprintf() will fail and mayfail, refer tofputc(3C) orfputwc(3C).
Thesnprintf() function will fail if:
The value ofn is greater thanINT_MAX or the number of bytes needed to hold the output excluding the terminating null is greater thanINT_MAX.
Theprintf(),fprintf(),sprintf(), andsnprintf() functions may fail if:
A wide-character code that does not correspond to a valid character has been detected.
There are insufficient arguments.
Theprintf(),fprintf(), andasprintf() functions may fail due to an underlyingmalloc(3C) failure if:
Storage space is temporarily unavailable.
Insufficient storage space is available.
If the application calling theprintf() functions has any objects of typewint_t orwchar_t, it must also include the header<wchar.h> to havethese objects defined.
It is common to use the following escape sequences built into theC language when entering format strings for theprintf() functions, but thesesequences are processed by the C compiler, not by theprintf() function.
Alert. Ring the bell.
Backspace. Move the printing position to one character before the current position, unless the current position is the start of a line.
Form feed. Move the printing position to the initial printing position of the next logical page.
Newline. Move the printing position to the start of the next line.
Carriage return. Move the printing position to the start of the current line.
Horizontal tab. Move the printing position to the next implementation-defined horizontal tab position on the current line.
Vertical tab. Move the printing position to the start of the next implementation-defined vertical tab position.
In addition, the C language supports character sequences of the form
\octal-number
and
\hex-number
which translates into the character represented by the octal or hexadecimal number.For example, if ASCII representations are being used, the letter 'a' maybe written as '\141' and 'Z' as '\132'. This syntax is mostfrequently used to represent the null character as '\0'. This is exactly equivalentto the numeric constant zero (0). Note that the octal number doesnot include the zero prefix as it would for a normal octalconstant. To specify a hexadecimal number, omit the zero so that theprefix is an 'x' (uppercase 'X' is not allowed in this context).Support for hexadecimal sequences is an ANSI extension. Seestandards(5).
Example 1 To print the language-independent date and time format, the following statement could be used:
printf (format, weekday, month, day, hour, min);
For American usage,format could be a pointer to the string:
"%s, %s %d, %d:%.2d\n"
producing the message:
Sunday, July 3, 10:02
whereas for German usage,format could be a pointer to the string:
"%1$s, %3$d. %2$s, %4$d:%5$.2d\n"
producing the message:
Sonntag, 3. Juli, 10:02
Example 2 To print a date and time in the formSunday, July 3, 10:02, whereweekday andmonth are pointers to null-terminated strings:
printf("%s, %s %i, %d:%.2d", weekday, month, day, hour, min);Example 3 To print pi to 5 decimal places:
printf("pi = %.5f", 4 * atan(1.0));Example 4 The following example applies only to applications that are not standard-conforming. To print a list of names in columns which are 20 characters wide:
printf("%20s%20s%20s", lastname, firstname, middlename);Seeattributes(5) for descriptions of the following attributes:
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All of these functions can be used safely in multithreaded applications, aslong assetlocale(3C) is not being called to change the locale. Thesprintf() andsnprintf() functions are Async-Signal-Safe.
Seestandards(5) for the standards conformance ofprintf(),fprintf(),sprintf(), andsnprintf().Theasprintf() function is modeled on the one that appears in theFreeBSD, NetBSD, and GNU C libraries.
exit(2),lseek(2),write(2),abort(3C),ecvt(3C),exit(3C),fclose(3C),fflush(3C),fputwc(3C),free(3C),malloc(3C),putc(3C),scanf(3C),setlocale(3C),stdio(3C),vprintf(3C),wcstombs(3C),wctomb(3C),attributes(5),environ(5),standards(5)
If thej length modifier is used, 32-bit applications that were compiledusingc89 on releases prior to Solaris 10 will experience undefined behavior.
Thesnprintf() return value whenn = 0 was changed in theSolaris 10 release. The change was based on the SUSv3 specification. Theprevious behavior was based on the initial SUSv2 specification, wheresnprintf() whenn = 0 returns an unspecified value less than 1.
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