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diff --git a/man-pages-posix-2017/man3p/fwscanf.3p b/man-pages-posix-2017/man3p/fwscanf.3p new file mode 100644 index 0000000..1b25679 --- /dev/null +++ b/man-pages-posix-2017/man3p/fwscanf.3p @@ -0,0 +1,874 @@ +'\" et +.TH FWSCANF "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.\" +.SH NAME +fwscanf, +swscanf, +wscanf +\(em convert formatted wide-character input +.SH SYNOPSIS +.LP +.nf +#include <stdio.h> +#include <wchar.h> +.P +int fwscanf(FILE *restrict \fIstream\fP, const wchar_t *restrict \fIformat\fP, ...); +int swscanf(const wchar_t *restrict \fIws\fP, + const wchar_t *restrict \fIformat\fP, ...); +int wscanf(const wchar_t *restrict \fIformat\fP, ...); +.fi +.SH DESCRIPTION +The functionality described on this reference page is aligned with the +ISO\ C standard. Any conflict between the requirements described here and the +ISO\ C standard is unintentional. This volume of POSIX.1\(hy2017 defers to the ISO\ C standard. +.P +The +\fIfwscanf\fR() +function shall read from the named input +.IR stream . +The +\fIwscanf\fR() +function shall read from the standard input stream +.IR stdin . +The +\fIswscanf\fR() +function shall read from the wide-character string +.IR ws . +Each function reads wide characters, interprets them according to a +format, and stores the results in its arguments. Each expects, as +arguments, a control wide-character string +.IR format +described below, and a set of +.IR pointer +arguments indicating where the converted input should be stored. The +result is undefined if there are insufficient arguments for the +format. If the +.IR format +is exhausted while arguments remain, the excess arguments are +evaluated but are otherwise ignored. +.P +Conversions can be applied to the +.IR n th +argument after the +.IR format +in the argument list, rather than to the next unused argument. In this +case, the conversion specifier wide character +.BR % +(see below) is replaced by the sequence +.BR \(dq%n$\(dq , +where +.IR n +is a decimal integer in the range [1,{NL_ARGMAX}]. +This feature provides for the definition of +.IR format +wide-character strings that select arguments in an order appropriate +to specific languages. In +.IR format +wide-character strings containing the \fR"%\fIn\fR$"\fR form of +conversion specifications, +it is unspecified whether numbered arguments in the argument list can +be referenced from the +.IR format +wide-character string more than once. +.P +The +.IR format +can contain either form of a conversion specification\(emthat is, +.BR % +or \fR"%\fIn\fR$"\fR\(em but the two forms cannot normally be mixed +within a single +.IR format +wide-character string. The only exception to this is that +.BR %% +or +.BR %* +can be mixed with the \fR"%\fIn\fR$"\fR form. When numbered argument +specifications are used, specifying the +.IR N th +argument requires that all the leading arguments, from the first to +the (\c +.IR N \-1)th, +are pointers. +.P +The +\fIfwscanf\fR() +function in all its forms allows for detection of a language-dependent +radix character in the input string, encoded as a wide-character +value. The radix character is defined in the current locale (category +.IR LC_NUMERIC ). +In the POSIX locale, or in a locale where the radix character is not +defined, the radix character shall default to a +<period> +(\c +.BR '.' ). +.P +The +.IR format +is a wide-character string composed of zero or more directives. Each +directive is composed of one of the following: +one or more white-space wide characters (\c +<space>, +<tab>, +<newline>, +<vertical-tab>, +or +<form-feed>); +an ordinary wide character (neither +.BR '%' +nor a white-space character); or a conversion specification. +It is unspecified whether an encoding error occurs if the +format string contains +.BR wchar_t +values that do not correspond to members of the character +set of the current locale and the specified semantics do not +require that value to be processed by +\fIwcrtomb\fR(). +.P +Each conversion specification is introduced by the +.BR '%' +or by the character sequence \fR"%\fIn\fR$"\fR, +after which the following appear in sequence: +.IP " *" 4 +An optional assignment-suppressing character +.BR '*' . +.IP " *" 4 +An optional non-zero decimal integer that specifies the maximum field +width. +.IP " *" 4 +An optional assignment-allocation character +.BR 'm' . +.IP " *" 4 +An optional length modifier that specifies the size of the receiving +object. +.IP " *" 4 +A conversion specifier wide character that specifies the type of +conversion to be applied. The valid conversion specifiers are described +below. +.P +The +\fIfwscanf\fR() +functions shall execute each directive of the format in turn. If a +directive fails, as detailed below, the function shall return. Failures +are described as input failures (due to the unavailability of input +bytes) or matching failures (due to inappropriate input). +.P +A directive composed of one or more white-space wide characters is +executed by reading input until no more valid input can be read, or up +to the first wide character which is not a white-space wide character, +which remains unread. +.P +A directive that is an ordinary wide character shall be executed as +follows. The next wide character is read from the input and compared +with the wide character that comprises the directive; if the comparison +shows that they are not equivalent, the directive shall fail, and the +differing and subsequent wide characters remain unread. Similarly, if +end-of-file, an encoding error, or a read error prevents a wide +character from being read, the directive shall fail. +.P +A directive that is a conversion specification defines a set of +matching input sequences, as described below for each conversion wide +character. A conversion specification is executed in the following +steps. +.P +Input white-space wide characters (as specified by +.IR "\fIiswspace\fR\^(\|)") +shall be skipped, unless the conversion specification includes a +.BR [ , +.BR c , +or +.BR n +conversion specifier. +.P +An item shall be read from the input, unless the conversion +specification includes an +.BR n +conversion specifier wide character. An input item is defined as the +longest sequence of input wide characters, not exceeding any specified +field width, which is an initial subsequence of a matching sequence. +The first wide character, if any, after the input item shall remain +unread. If the length of the input item is zero, the execution of the +conversion specification shall fail; this condition is a matching +failure, unless end-of-file, an encoding error, or a read error +prevented input from the stream, in which case it is an input failure. +.P +Except in the case of a +.BR % +conversion specifier, the input item (or, in the case of a +.BR %n +conversion specification, the count of input wide characters) shall be +converted to a type appropriate to the conversion wide character. If +the input item is not a matching sequence, the execution of the +conversion specification shall fail; this condition is a matching +failure. Unless assignment suppression was indicated by a +.BR '*' , +the result of the conversion shall be placed in the object pointed to +by the first argument following the +.IR format +argument that has not already received a conversion result if the +conversion specification is introduced by +.BR % , +or in the +.IR n th +argument if introduced by the wide-character sequence +\fR"%\fIn\fR$"\fR. +If this object does not have an appropriate type, or if the result +of the conversion cannot be represented in the space provided, the +behavior is undefined. +.P +The +.BR %c , +.BR %s , +and +.BR %[ +conversion specifiers shall accept an optional assignment-allocation +character +.BR 'm' , +which shall cause a memory buffer to be allocated to hold the +wide-character string converted including a terminating null wide +character. In such a case, the argument corresponding to the conversion +specifier should be a reference to a pointer value that will receive a +pointer to the allocated buffer. The system shall allocate a buffer as if +\fImalloc\fR() +had been called. The application shall be responsible for freeing the +memory after usage. If there is insufficient memory to allocate a buffer, +the function shall set +.IR errno +to +.BR [ENOMEM] +and a conversion error shall result. If the function returns EOF, any +memory successfully allocated for parameters using assignment-allocation +character +.BR 'm' +by this call shall be freed before the function returns. +.br +.P +The length modifiers and their meanings are: +.IP "\fRhh\fR" 8 +Specifies that a following +.BR d , +.BR i , +.BR o , +.BR u , +.BR x , +.BR X , +or +.BR n +conversion specifier applies to an argument with type pointer to +.BR "signed char" +or +.BR "unsigned char" . +.IP "\fRh\fR" 8 +Specifies that a following +.BR d , +.BR i , +.BR o , +.BR u , +.BR x , +.BR X , +or +.BR n +conversion specifier applies to an argument with type pointer to +.BR "short" +or +.BR "unsigned short" . +.IP "\fRl\fR\ (ell)" 8 +Specifies that a following +.BR d , +.BR i , +.BR o , +.BR u , +.BR x , +.BR X , +or +.BR n +conversion specifier applies to an argument with type pointer to +.BR "long" +or +.BR "unsigned long" ; +that a following +.BR a , +.BR A , +.BR e , +.BR E , +.BR f , +.BR F , +.BR g , +or +.BR G +conversion specifier applies to an argument with type pointer to +.BR double ; +or that a following +.BR c , +.BR s , +or +.BR [ +conversion specifier applies to an argument with type pointer to +.BR wchar_t . +If the +.BR 'm' +assignment-allocation character is specified, the conversion applies +to an argument with the type pointer to a pointer to +.BR wchar_t . +.IP "\fRll\fR\ (ell-ell)" 8 +.br +Specifies that a following +.BR d , +.BR i , +.BR o , +.BR u , +.BR x , +.BR X , +or +.BR n +conversion specifier applies to an argument with type pointer to +.BR "long long" +or +.BR "unsigned long long" . +.IP "\fRj\fR" 8 +Specifies that a following +.BR d , +.BR i , +.BR o , +.BR u , +.BR x , +.BR X , +or +.BR n +conversion specifier applies to an argument with type pointer to +.BR intmax_t +or +.BR uintmax_t . +.IP "\fRz\fR" 8 +Specifies that a following +.BR d , +.BR i , +.BR o , +.BR u , +.BR x , +.BR X , +or +.BR n +conversion specifier applies to an argument with type pointer to +.BR size_t +or the corresponding signed integer type. +.IP "\fRt\fR" 8 +Specifies that a following +.BR d , +.BR i , +.BR o , +.BR u , +.BR x , +.BR X , +or +.BR n +conversion specifier applies to an argument with type pointer to +.BR ptrdiff_t +or the corresponding +.BR unsigned +type. +.IP "\fRL\fR" 8 +Specifies that a following +.BR a , +.BR A , +.BR e , +.BR E , +.BR f , +.BR F , +.BR g , +or +.BR G +conversion specifier applies to an argument with type pointer to +.BR "long double" . +.P +If a length modifier appears with any conversion specifier other than +as specified above, the behavior is undefined. +.P +The following conversion specifier wide characters are valid: +.IP "\fRd\fP" 8 +Matches an optionally signed decimal integer, whose format is the same +as expected for the subject sequence of +\fIwcstol\fR() +with the value 10 for the +.IR base +argument. In the absence of a size modifier, the application shall ensure +that the corresponding argument is a pointer to +.BR int . +.IP "\fRi\fP" 8 +Matches an optionally signed integer, whose format is the same as +expected for the subject sequence of +\fIwcstol\fR() +with 0 for the +.IR base +argument. In the absence of a size modifier, the application shall +ensure that the corresponding argument is a pointer to +.BR int . +.IP "\fRo\fP" 8 +Matches an optionally signed octal integer, whose format is the same as +expected for the subject sequence of +\fIwcstoul\fR() +with the value 8 for the +.IR base +argument. In the absence of a size modifier, the application shall +ensure that the corresponding argument is a pointer to +.BR unsigned . +.IP "\fRu\fP" 8 +Matches an optionally signed decimal integer, whose format is the same +as expected for the subject sequence of +\fIwcstoul\fR() +with the value 10 for the +.IR base +argument. In the absence of a size modifier, the application shall +ensure that the corresponding argument is a pointer to +.BR unsigned . +.IP "\fRx\fP" 8 +Matches an optionally signed hexadecimal integer, whose format is the +same as expected for the subject sequence of +\fIwcstoul\fR() +with the value 16 for the +.IR base +argument. In the absence of a size modifier, the application shall +ensure that the corresponding argument is a pointer to +.BR unsigned . +.IP "\fRa\fR,\ \fRe\fP,\ \fRf\fP,\ \fRg\fP" 8 +.br +Matches an optionally signed floating-point number, infinity, or NaN +whose format is the same as expected for the subject sequence of +\fIwcstod\fR(). +In the absence of a size modifier, the application shall ensure that +the corresponding argument is a pointer to +.BR float . +.RS 8 +.P +If the +\fIfwprintf\fR() +family of functions generates character string representations for +infinity and NaN (a symbolic entity encoded in floating-point +format) to support IEEE\ Std\ 754\(hy1985, the +\fIfwscanf\fR() +family of functions shall recognize them as input. +.RE +.IP "\fRs\fP" 8 +Matches a sequence of non-white-space wide characters. If no +.BR l +(ell) qualifier is present, characters from the input field shall be +converted as if by repeated calls to the +\fIwcrtomb\fR() +function, with the conversion state described by an +.BR mbstate_t +object initialized to zero before the first wide character is +converted. If the +.BR 'm' +assignment-allocation character is not specified, the application shall +ensure that the corresponding argument is a pointer to a character array +large enough to accept the sequence and the terminating null character, +which shall be added automatically. +Otherwise, the application shall ensure that the corresponding +argument is a pointer to a pointer to a +.BR wchar_t . +.RS 8 +.P +If the +.BR l +(ell) qualifier is present and the +.BR 'm' +assignment-allocation character is not specified, the application shall +ensure that the corresponding argument is a pointer to an array of +.BR wchar_t +large enough to accept the sequence and the terminating null wide +character, which shall be added automatically. +If the +.BR l +(ell) qualifier is present and the +.BR 'm' +assignment-allocation character is present, the application shall +ensure that the corresponding argument is a pointer to a pointer +to a +.BR wchar_t . +.RE +.IP "\fR[\fR" 8 +Matches a non-empty sequence of wide characters from a set of expected +wide characters (the +.IR scanset ). +If no +.BR l +(ell) qualifier is present, wide characters from the input field shall +be converted as if by repeated calls to the +\fIwcrtomb\fR() +function, with the conversion state described by an +.BR mbstate_t +object initialized to zero before the first wide character is +converted. If the +.BR 'm' +assignment-allocation character is not specified, the application shall +ensure that the corresponding argument is a pointer to a character array +large enough to accept the sequence and the terminating null character, +which shall be added automatically. +Otherwise, the application shall ensure that the corresponding +argument is a pointer to a pointer to a +.BR wchar_t . +.RS 8 +.P +If an +.BR l +(ell) qualifier is present and the +.BR 'm' +assignment-allocation character is not specified, the application shall +ensure that the corresponding argument is a pointer to an array of +.BR wchar_t +large enough to accept the sequence and the terminating null +wide character. +If an +.BR l +(ell) qualifier is present and the +.BR 'm' +assignment-allocation character is specified, the application shall +ensure that the corresponding argument is a pointer to a pointer +to a +.BR wchar_t . +.P +The conversion specification includes all subsequent wide characters in +the +.IR format +string up to and including the matching +<right-square-bracket> +(\c +.BR ']' ). +The wide characters between the square brackets (the +.IR scanlist ) +comprise the scanset, unless the wide character after the +<left-square-bracket> +is a +<circumflex> +(\c +.BR '\(ha' ), +in which case the scanset contains all wide characters that do not +appear in the scanlist between the +<circumflex> +and the +<right-square-bracket>. +If the conversion specification begins with +.BR \(dq[\|]\(dq +or +.BR \(dq[\(ha]\(dq , +the +<right-square-bracket> +is included in the scanlist and the next +<right-square-bracket> +is the matching +<right-square-bracket> +that ends the conversion specification; otherwise, the first +<right-square-bracket> +is the one that ends the conversion specification. If a +.BR '\-' +is in the scanlist and is not the first wide character, nor the second +where the first wide character is a +.BR '\(ha' , +nor the last wide character, the behavior is implementation-defined. +.RE +.IP "\fRc\fP" 8 +Matches a sequence of wide characters of exactly the number specified +by the field width (1 if no field width is present in the conversion +specification). +.RS 8 +.P +If no +.BR l +(ell) length modifier is present, characters from the input field shall +be converted as if by repeated calls to the +\fIwcrtomb\fR() +function, with the conversion state described by an +.BR mbstate_t +object initialized to zero before the first wide character is +converted. No null character is added. If the +.BR 'm' +assignment-allocation character is not specified, the application +shall ensure that the corresponding argument is a pointer to the +initial element of a character array large enough to accept the sequence. +Otherwise, the application shall ensure that the corresponding +argument is a pointer to a pointer to a +.BR char . +.P +No null wide character is added. If an +.BR l +(ell) length modifier is present and the +.BR 'm' +assignment-allocation character is not specified, the application shall +ensure that the corresponding argument shall be a pointer to the initial +element of an array of +.BR wchar_t +large enough to accept the sequence. +If an +.BR l +(ell) qualifier is present and the +.BR 'm' +assignment-allocation character is specified, the application shall +ensure that the corresponding argument is a pointer to a pointer +to a +.BR wchar_t . +.RE +.IP "\fRp\fP" 8 +Matches an implementation-defined set of sequences, which shall be +the same as the set of sequences that is produced by the +.BR %p +conversion specification of the corresponding +\fIfwprintf\fR() +functions. The application shall ensure that the corresponding argument +is a pointer to a pointer to +.BR void . +The interpretation of the input item is implementation-defined. If +the input item is a value converted earlier during the same program +execution, the pointer that results shall compare equal to that value; +otherwise, the behavior of the +.BR %p +conversion is undefined. +.IP "\fRn\fP" 8 +No input is consumed. The application shall ensure that the +corresponding argument is a pointer to the integer into which is to be +written the number of wide characters read from the input so far by +this call to the +\fIfwscanf\fR() +functions. Execution of a +.BR %n +conversion specification shall not increment the assignment count +returned at the completion of execution of the function. No argument +shall be converted, but one shall be consumed. If the conversion +specification includes an assignment-suppressing wide character or a +field width, the behavior is undefined. +.IP "\fRC\fP" 8 +Equivalent to +.BR lc . +.IP "\fRS\fP" 8 +Equivalent to +.BR ls . +.IP "\fR%\fR" 8 +Matches a single +.BR '%' +wide character; no conversion or assignment shall occur. The complete +conversion specification shall be +.BR %% . +.P +If a conversion specification is invalid, the behavior is undefined. +.P +The conversion specifiers +.BR A , +.BR E , +.BR F , +.BR G , +and +.BR X +are also valid and shall be equivalent to, respectively, +.BR a , +.BR e , +.BR f , +.BR g , +and +.BR x . +.P +If end-of-file is encountered during input, conversion is terminated. +If end-of-file occurs before any wide characters matching the current +conversion specification (except for +.BR %n ) +have been read (other than leading white-space, where permitted), +execution of the current conversion specification shall terminate with +an input failure. Otherwise, unless execution of the current conversion +specification is terminated with a matching failure, execution of the +following conversion specification (if any) shall be terminated with an +input failure. +.P +Reaching the end of the string in +\fIswscanf\fR() +shall be equivalent to encountering end-of-file for +\fIfwscanf\fR(). +.P +If conversion terminates on a conflicting input, the offending input +shall be left unread in the input. Any trailing white space (including +<newline>) +shall be left unread unless matched by a conversion specification. The +success of literal matches and suppressed assignments is only directly +determinable via the +.BR %n +conversion specification. +.P +The +\fIfwscanf\fR() +and +\fIwscanf\fR() +functions may mark the last data access timestamp of the file +associated with +.IR stream +for update. The last data access timestamp shall be marked for update +by the first successful execution of +\fIfgetwc\fR(), +\fIfgetws\fR(), +\fIfwscanf\fR(), +\fIgetwc\fR(), +\fIgetwchar\fR(), +\fIvfwscanf\fR(), +\fIvwscanf\fR(), +or +\fIwscanf\fR() +using +.IR stream +that returns data not supplied by a prior call to +\fIungetwc\fR(). +.SH "RETURN VALUE" +Upon successful completion, these functions shall return the number of +successfully matched and assigned input items; this number can be zero +in the event of an early matching failure. If the input ends before +the first conversion (if any) has completed, and without a +matching failure having occurred, EOF shall be returned. If an +error occurs before the first conversion (if any) has completed, +and without a matching failure having occurred, EOF shall be returned +and +.IR errno +shall be set to indicate the error. +If a read error occurs, the error indicator for the stream shall be set. +.SH ERRORS +For the conditions under which the +\fIfwscanf\fR() +functions shall fail and may fail, refer to +.IR "\fIfgetwc\fR\^(\|)". +.P +In addition, the +\fIfwscanf\fR() +function shall fail if: +.TP +.BR EILSEQ +Input byte sequence does not form a valid character. +.TP +.BR ENOMEM +Insufficient storage space is available. +.P +In addition, the +\fIfwscanf\fR() +function may fail if: +.TP +.BR EINVAL +There are insufficient arguments. +.LP +.IR "The following sections are informative." +.SH "EXAMPLES" +The call: +.sp +.RS 4 +.nf + +int i, n; float x; char name[50]; +n = wscanf(L"%d%f%s", &i, &x, name); +.fi +.P +.RE +.P +with the input line: +.sp +.RS 4 +.nf + +25 54.32E-1 Hamster +.fi +.P +.RE +.P +assigns to +.IR n +the value 3, to +.IR i +the value 25, to +.IR x +the value 5.432, and +.IR name +contains the string +.BR \(dqHamster\(dq . +.P +The call: +.sp +.RS 4 +.nf + +int i; float x; char name[50]; +(void) wscanf(L"%2d%f%*d %[0123456789]", &i, &x, name); +.fi +.P +.RE +.P +with input: +.sp +.RS 4 +.nf + +56789 0123 56a72 +.fi +.P +.RE +.P +assigns 56 to +.IR i , +789.0 to +.IR x , +skips 0123, and places the string +.BR \(dq56\e0\(dq +in +.IR name . +The next call to +\fIgetchar\fR() +shall return the character +.BR 'a' . +.SH "APPLICATION USAGE" +In format strings containing the +.BR '%' +form of conversion specifications, each argument in the argument +list is used exactly once. +.P +For functions that allocate memory as if by +\fImalloc\fR(), +the application should release such memory when it is no longer +required by a call to +\fIfree\fR(). +For +\fIfwscanf\fR(), +this is memory allocated via use of the +.BR 'm' +assignment-allocation character. +.SH RATIONALE +None. +.SH "FUTURE DIRECTIONS" +None. +.SH "SEE ALSO" +.IR "Section 2.5" ", " "Standard I/O Streams", +.IR "\fIgetwc\fR\^(\|)", +.IR "\fIfwprintf\fR\^(\|)", +.IR "\fIsetlocale\fR\^(\|)", +.IR "\fIwcstod\fR\^(\|)", +.IR "\fIwcstol\fR\^(\|)", +.IR "\fIwcstoul\fR\^(\|)", +.IR "\fIwcrtomb\fR\^(\|)" +.P +The Base Definitions volume of POSIX.1\(hy2017, +.IR "Chapter 7" ", " "Locale", +.IR "\fB<inttypes.h>\fP", +.IR "\fB<stdio.h>\fP", +.IR "\fB<wchar.h>\fP" +.\" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1-2017, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, 2018 Edition, +Copyright (C) 2018 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +In the event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . +.PP +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |