NAME
ssccaannff, ffssccaannff, ssssccaannff, vvssccaannff, vvssssccaannff, vvffssccaannff - input format conver-
sion LLIIBBRRAARRYYStandard C Library (libc, -lc)
SYNOPSIS
##iinncclluuddee <
int ssccaannff(const char * restrict format, ...); int ffssccaannff(FILE * restrict stream, const char * restrict format, ...); int ssssccaannff(const char * restrict str, const char * restrict format, ...);> ##iinncclluuddee <
int vvssccaannff(const char * restrict format, valist ap); int vvssssccaannff(const char * restrict str, const char * restrict format, valist ap); int vvffssccaannff(FILE * restrict stream, const char * restrict format, valist ap);> DESCRIPTION
The ssccaannff() family of functions scans input according to a format as described below. This format may contain conversion specifiers; the results from such conversions, if any, are stored through the pointer arguments. The ssccaannff() function reads input from the standard input stream stdin, ffssccaannff() reads input from the stream pointer stream, and ssssccaannff() reads its input from the character string pointed to by str. The vvffssccaannff() function is analogous to vfprintf(3) and reads input from the stream pointer stream using a variable argument list of pointers (see stdarg(3)). The vvssccaannff() function scans a variable argument list from the standard input and the vvssssccaannff() function scans it from a string;these are analogous to the vvpprriinnttff() and vvsspprriinnttff() functions respec-
tively. Each successive pointer argument must correspond properly witheach successive conversion specifier (but see the ** and %%nn$$ conversions
below). All conversions are introduced by the %% (percent sign) character
or %%nn$$ sequence. In the latter case the next pointer will be the nn th
argument after the format string. The format string may also contain other characters. White space (such as blanks, tabs, or newlines) in the format string match any amount of white space, including none, in the input. Everything else matches only itself. Scanning stops when an input character does not match such a format character. Scanning also stops when an input conversion cannot be made (see below). Extended locale versions of these functions are documented in scanfl(3). See xlocale(3) for more information. CCOONNVVEERRSSIIOONNSSFollowing the %% character or %%nn$$ sequence introducing a conversion there
may be a number of flag characters, as follows: ** Suppresses assignment. The conversion that follows occurs as usual, but no pointer is used; the result of the conversion is simply discarded. hhhh Indicates that the conversion will be one of ddiioouuxx or nn and the next pointer is a pointer to a char (rather than int). hh Indicates that the conversion will be one of ddiioouuxx or nn and the next pointer is a pointer to a short int (rather than int). ll (ell) Indicates that the conversion will be one of ddiioouuxx or nn and the next pointer is a pointer to a long int (rather than int), that the conversion will be one of aa, ee, ff, or gg and the next pointeris a pointer to double (rather than float), or that the conver-
sion will be one of cc, ss or [[ and the next pointer is a pointer to an array of wchart (rather than char). llll (ell ell) Indicates that the conversion will be one of ddiioouuxx or nn and the next pointer is a pointer to a long long int (rather than int). LL Indicates that the conversion will be one of aa, ee, ff, or gg and the next pointer is a pointer to long double. jj Indicates that the conversion will be one of ddiioouuxx or nn and the next pointer is a pointer to a intmaxt (rather than int). tt Indicates that the conversion will be one of ddiioouuxx or nn and the next pointer is a pointer to a ptrdifft (rather than int). zz Indicates that the conversion will be one of ddiioouuxx or nn and the next pointer is a pointer to a sizet (rather than int). qq (deprecated.) Indicates that the conversion will be one of ddiioouuxx or nn and the next pointer is a pointer to a long long int (rather than int). In addition to these flags, there may be an optional maximum field width,expressed as a decimal integer, between the %% and the conversion. If no
width is given, a default of ``infinity'' is used (with one exception, below); otherwise at most this many bytes are scanned in processing the conversion. In the case of the llcc, llss and ll[[ conversions, the field width specifies the maximum number of multibyte characters that will be scanned. Before conversion begins, most conversions skip white space; this white space is not counted against the field width. The following conversions are available:%% Matches a literal `%'. That is, ``%%'' in the format string
matches a single input `%' character. No conversion is done, and
assignment does not occur. dd Matches an optionally signed decimal integer; the next pointer must be a pointer to int. ii Matches an optionally signed integer; the next pointer must be a pointer to int. The integer is read in base 16 if it begins with`0x' or `0X', in base 8 if it begins with `0', and in base 10 oth-
erwise. Only characters that correspond to the base are used. oo Matches an octal integer; the next pointer must be a pointer to unsigned int. uu Matches an optionally signed decimal integer; the next pointer must be a pointer to unsigned int. xx, XX Matches an optionally signed hexadecimal integer; the next pointer must be a pointer to unsigned int. aa, AA, ee, EE, ff, FF, gg, GGMatches a floating-point number in the style of strtod(3). The
next pointer must be a pointer to float (unless ll or LL is speci-
fied.)ss Matches a sequence of non-white-space characters; the next pointer
must be a pointer to char, and the array must be large enough to accept all the sequence and the terminating NUL character. The input string stops at white space or at the maximum field width, whichever occurs first. If an ll qualifier is present, the next pointer must be a pointer to wchart, into which the input will be placed after conversion by mbrtowc(3). SS The same as llss. cc Matches a sequence of width count characters (default 1); the next pointer must be a pointer to char, and there must be enough room for all the characters (no terminating NUL is added). The usual skip of leading white space is suppressed. To skip white space first, use an explicit space in the format. If an ll qualifier is present, the next pointer must be a pointer to wchart, into which the input will be placed after conversion by mbrtowc(3). CC The same as llcc. [[ Matches a nonempty sequence of characters from the specified set of accepted characters; the next pointer must be a pointer to char, and there must be enough room for all the characters in the string, plus a terminating NUL character. The usual skip of leading white space is suppressed. The string is to be made up of characters in (or not in) a particular set; the set is defined by the charactersbetween the open bracket [ character and a close bracket ] charac-
ter. The set excludes those characters if the first character after the open bracket is a circumflex ^^. To include a close bracket in the set, make it the first character after the open bracket or the circumflex; any other position will end the set.The hyphen character - is also special; when placed between two
other characters, it adds all intervening characters to the set. To include a hyphen, make it the last character before the finalclose bracket. For instance, `[^]0-9-]' means the set ``everything
except close bracket, zero through nine, and hyphen''. The stringends with the appearance of a character not in the (or, with a cir-
cumflex, in) set or when the field width runs out. If an ll qualifier is present, the next pointer must be a pointer to wchart, into which the input will be placed after conversion by mbrtowc(3).pp Matches a pointer value (as printed by `%p' in printf(3)); the next
pointer must be a pointer to void. nn Nothing is expected; instead, the number of characters consumed thus far from the input is stored through the next pointer, which must be a pointer to int. This is not a conversion, although it can be suppressed with the ** flag. The decimal point character is defined in the program's locale (category LCNUMERIC).For backwards compatibility, a ``conversion'' of `%\0' causes an immedi-
ate return of EOF.RETURN VALUES
These functions return the number of input items assigned, which can befewer than provided for, or even zero, in the event of a matching fail-
ure. Zero indicates that, while there was input available, no conver-
sions were assigned; typically this is due to an invalid input character,such as an alphabetic character for a `%d' conversion. The value EOF is
returned if an input failure occurs before any conversion such as an end-
of-file occurs. If an error or end-of-file occurs after conversion has
begun, the number of conversions which were successfully completed is returned.SEE ALSO
getc(3), mbrtowc(3), printf(3), strtod(3), strtol(3), strtoul(3), wscanf(3), scanfl(3) STANDARDS The functions ffssccaannff(), ssccaannff(), ssssccaannff(), vvffssccaannff(), vvssccaannff() and vvssssccaannff() conform to ISO/IEC 9899:1999 (``ISO C99'').BUGS
Earlier implementations of ssccaannff treated %%DD, %%EE, %%FF, %%OO and %%XX as their
lowercase equivalents with an ll modifier. In addition, ssccaannff treated anunknown conversion character as %%dd or %%DD, depending on its case. This
functionality has been removed.Numerical strings are truncated to 512 characters; for example, %%ff and %%dd
are implicitly %%551122ff and %%551122dd.
The ssccaannff family of functions do not correctly handle multibyte charac-
ters in the format argument. BSD January 4, 2003 BSD