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- '\"
- '\" Copyright (c) 1993 The Regents of the University of California.
- '\" All rights reserved.
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- '\" license or royalty fees, to use, copy, modify, and distribute this
- '\" documentation for any purpose, provided that the above copyright
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- '\" FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
- '\" ARISING OUT OF THE USE OF THIS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
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- '\"
- '\" $Header: /user6/ouster/tcl/man/RCS/format.n,v 1.4 93/08/05 13:56:19 ouster Exp $ SPRITE (Berkeley)
- '\"
- .\" The definitions below are for supplemental macros used in Tcl/Tk
- .\" manual entries.
- .\"
- .\" .HS name section [date [version]]
- .\" Replacement for .TH in other man pages. See below for valid
- .\" section names.
- .\"
- .\" .AP type name in/out [indent]
- .\" Start paragraph describing an argument to a library procedure.
- .\" type is type of argument (int, etc.), in/out is either "in", "out",
- .\" or "in/out" to describe whether procedure reads or modifies arg,
- .\" and indent is equivalent to second arg of .IP (shouldn't ever be
- .\" needed; use .AS below instead)
- .\"
- .\" .AS [type [name]]
- .\" Give maximum sizes of arguments for setting tab stops. Type and
- .\" name are examples of largest possible arguments that will be passed
- .\" to .AP later. If args are omitted, default tab stops are used.
- .\"
- .\" .BS
- .\" Start box enclosure. From here until next .BE, everything will be
- .\" enclosed in one large box.
- .\"
- .\" .BE
- .\" End of box enclosure.
- .\"
- .\" .VS
- .\" Begin vertical sidebar, for use in marking newly-changed parts
- .\" of man pages.
- .\"
- .\" .VE
- .\" End of vertical sidebar.
- .\"
- .\" .DS
- .\" Begin an indented unfilled display.
- .\"
- .\" .DE
- .\" End of indented unfilled display.
- .\"
- '\" # Heading for Tcl/Tk man pages
- .de HS
- .ds ^3 \\0
- .if !"\\$3"" .ds ^3 \\$3
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- .if '\\$2'tkc' .TH \\$1 3 \\*(^3 Tk "Tk Library Procedures"
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- .if '\\$2'tkcmds' .TH \\$1 1 \\*(^3 Tk "Tk Applications"
- .if t .wh -1.3i ^B
- .nr ^l \\n(.l
- .ad b
- ..
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- . el .TP 15
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- \&\\$1 \\fI\\$2\\fP (\\$3)
- .\".b
- .\}
- .el \{\
- .br
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- \&\\$1 \\fI\\$2\\fP
- .\}
- .el \{\
- \&\\fI\\$1\\fP
- .\}
- .\}
- ..
- '\" # define tabbing values for .AP
- .de AS
- .nr )A 10n
- .if !"\\$1"" .nr )A \\w'\\$1'u+3n
- .nr )B \\n()Au+15n
- .\"
- .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n
- .nr )C \\n()Bu+\\w'(in/out)'u+2n
- ..
- '\" # BS - start boxed text
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- .if n \l'\\n(.lu\(ul'
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- .ie !\\n(^b-1 \{\
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- \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
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- .br
- .nr ^b 0
- ..
- '\" # VS - start vertical sidebar
- '\" # ^Y = starting y location
- '\" # ^v = 1 (for troff; for nroff this doesn't matter)
- .de VS
- .mk ^Y
- .ie n 'mc \s12\(br\s0
- .el .nr ^v 1u
- ..
- '\" # VE - end of vertical sidebar
- .de VE
- .ie n 'mc
- .el \{\
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- .sp -1
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- .ev
- .\}
- .nr ^v 0
- ..
- '\" # Special macro to handle page bottom: finish off current
- '\" # box/sidebar if in box/sidebar mode, then invoked standard
- '\" # page bottom macro.
- .de ^B
- .ev 2
- 'ti 0
- 'nf
- .mk ^t
- .if \\n(^b \{\
- .\" Draw three-sided box if this is the box's first page,
- .\" draw two sides but no top otherwise.
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- .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c
- .\}
- .if \\n(^v \{\
- .nr ^x \\n(^tu+1v-\\n(^Yu
- \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c
- .\}
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- 'fi
- .ev
- .if \\n(^b \{\
- .mk ^y
- .nr ^b 2
- .\}
- .if \\n(^v \{\
- .mk ^Y
- .\}
- ..
- '\" # DS - begin display
- .de DS
- .RS
- .nf
- .sp
- ..
- '\" # DE - end display
- .de DE
- .fi
- .RE
- .sp .5
- ..
- .HS format tcl
- .BS
- '\" Note: do not modify the .SH NAME line immediately below!
- .SH NAME
- format \- Format a string in the style of sprintf
- .SH SYNOPSIS
- \fBformat \fIformatString \fR?\fIarg arg ...\fR?
- .BE
-
- .SH INTRODUCTION
- .PP
- This command generates a formatted string in the same way as the
- ANSI C \fBsprintf\fR procedure (it uses \fBsprintf\fR in its
- implementation).
- \fIFormatString\fR indicates how to format the result, using
- \fB%\fR conversion specifiers as in \fBsprintf\fR, and the additional
- arguments, if any, provide values to be substituted into the result.
- The return value from \fBformat\fR is the formatted string.
-
- .SH "DETAILS ON FORMATTING"
- .PP
- The command operates by scanning \fIformatString\fR from left to right.
- Each character from the format string is appended to the result
- string unless it is a percent sign.
- If the character is a \fB%\fR then it is not copied to the result string.
- Instead, the characters following the \fB%\fR character are treated as
- a conversion specifier.
- The conversion specifier controls the conversion of the next successive
- \fIarg\fR to a particular format and the result is appended to
- the result string in place of the conversion specifier.
- If there are multiple conversion specifiers in the format string,
- then each one controls the conversion of one additional \fIarg\fR.
- The \fBformat\fR command must be given enough \fIarg\fRs to meet the needs
- of all of the conversion specifiers in \fIformatString\fR.
- .PP
- Each conversion specifier may contain up to six different parts:
- .VS
- an XPG3 position specifier,
- .VE
- a set of flags, a minimum field width, a precision, a length modifier,
- and a conversion character.
- Any of these fields may be omitted except for the conversion character.
- The fields that are present must appear in the order given above.
- The paragraphs below discuss each of these fields in turn.
- .PP
- .VS
- If the \fB%\fR is followed by a decimal number and a \fB$\fR, as in
- ``\fB%2$d\fR'', then the value to convert is not taken from the
- next sequential argument.
- Instead, it is taken from the argument indicated by the number,
- where 1 corresponds to the first \fIarg\fR.
- If the conversion specifier requires multiple arguments because
- of \fB*\fR characters in the specifier then
- successive arguments are used, starting with the argument
- given by the number.
- This follows the XPG3 conventions for positional specifiers.
- If there are any positional specifiers in \fIformatString\fR
- then all of the specifiers must be positional.
- .VE
- .PP
- The second portion of a conversion specifier may contain any of the
- following flag characters, in any order:
- .TP 10
- \fB\-\fR
- Specifies that the converted argument should be left-justified
- in its field (numbers are normally right-justified with leading
- spaces if needed).
- .TP 10
- \fB+\fR
- Specifies that a number should always be printed with a sign,
- even if positive.
- .TP 10
- \fIspace\fR
- Specifies that a space should be added to the beginning of the
- number if the first character isn't a sign.
- .TP 10
- \fB0\fR
- Specifies that the number should be padded on the left with
- zeroes instead of spaces.
- .TP 10
- \fB#\fR
- Requests an alternate output form. For \fBo\fR and \fBO\fR
- conversions it guarantees that the first digit is always \fB0\fR.
- For \fBx\fR or \fBX\fR conversions, \fB0x\fR or \fB0X\fR (respectively)
- will be added to the beginning of the result unless it is zero.
- For all floating-point conversions (\fBe\fR, \fBE\fR, \fBf\fR,
- \fBg\fR, and \fBG\fR) it guarantees that the result always
- has a decimal point.
- For \fBg\fR and \fBG\fR conversions it specifies that
- trailing zeroes should not be removed.
- .PP
- The third portion of a conversion specifier is a number giving a
- minimum field width for this conversion.
- It is typically used to make columns line up in tabular printouts.
- If the converted argument contains fewer characters than the
- minimum field width then it will be padded so that it is as wide
- as the minimum field width.
- Padding normally occurs by adding extra spaces on the left of the
- converted argument, but the \fB0\fR and \fB\-\fR flags
- may be used to specify padding with zeroes on the left or with
- spaces on the right, respectively.
- If the minimum field width is specified as \fB*\fR rather than
- a number, then the next argument to the \fBformat\fR command
- determines the minimum field width; it must be a numeric string.
- .PP
- The fourth portion of a conversion specifier is a precision,
- which consists of a period followed by a number.
- The number is used in different ways for different conversions.
- For \fBe\fR, \fBE\fR, and \fBf\fR conversions it specifies the number
- of digits to appear to the right of the decimal point.
- For \fBg\fR and \fBG\fR conversions it specifies the total number
- of digits to appear, including those on both sides of the decimal
- point (however, trailing zeroes after the decimal point will still
- be omitted unless the \fB#\fR flag has been specified).
- For integer conversions, it specifies a mimimum number of digits
- to print (leading zeroes will be added if necessary).
- For \fBs\fR conversions it specifies the maximum number of characters to be
- printed; if the string is longer than this then the trailing characters will be dropped.
- If the precision is specified with \fB*\fR rather than a number
- then the next argument to the \fBformat\fR command determines the precision;
- it must be a numeric string.
- .PP
- The fourth part of a conversion specifier is a length modifier,
- which must be \fBh\fR or \fBl\fR.
- If it is \fBh\fR it specifies that the numeric value should be
- truncated to a 16-bit value before converting.
- This option is rarely useful.
- The \fBl\fR modifier is ignored.
- .PP
- The last thing in a conversion specifier is an alphabetic character
- that determines what kind of conversion to perform.
- The following conversion characters are currently supported:
- .TP 10
- \fBd\fR
- Convert integer to signed decimal string.
- .TP 10
- \fBu\fR
- Convert integer to unsigned decimal string.
- .TP 10
- \fBi\fR
- Convert integer to signed decimal string; the integer may either be
- in decimal, in octal (with a leading \fB0\fR) or in hexadecimal
- (with a leading \fB0x\fR).
- .TP 10
- \fBo\fR
- Convert integer to unsigned octal string.
- .TP 10
- \fBx\fR or \fBX\fR
- Convert integer to unsigned hexadecimal string, using digits
- ``0123456789abcdef'' for \fBx\fR and ``0123456789ABCDEF'' for \fBX\fR).
- .TP 10
- \fBc\fR
- Convert integer to the 8-bit character it represents.
- .TP 10
- \fBs\fR
- No conversion; just insert string.
- .TP 10
- \fBf\fR
- Convert floating-point number to signed decimal string of
- the form \fIxx.yyy\fR, where the number of \fIy\fR's is determined by
- the precision (default: 6).
- If the precision is 0 then no decimal point is output.
- .TP 10
- \fBe\fR or \fBe\fR
- Convert floating-point number to scientific notation in the
- form \fIx.yyy\fBe\(+-\fIzz\fR, where the number of \fIy\fR's is determined
- by the precision (default: 6).
- If the precision is 0 then no decimal point is output.
- If the \fBE\fR form is used then \fBE\fR is
- printed instead of \fBe\fR.
- .TP 10
- \fBg\fR or \fBG\fR
- If the exponent is less than \-4 or greater than or equal to the
- precision, then convert floating-point number as for \fB%e\fR or
- \fB%E\fR.
- Otherwise convert as for \fB%f\fR.
- Trailing zeroes and a trailing decimal point are omitted.
- .TP 10
- \fB%\fR
- No conversion: just insert \fB%\fR.
- .LP
- For the numerical conversions the argument being converted must
- be an integer or floating-point string; format converts the argument
- to binary and then converts it back to a string according to
- the conversion specifier.
-
- .SH "DIFFERENCES FROM ANSI SPRINTF"
- .PP
- .VS
- The behavior of the format command is the same as the
- ANSI C \fBsprintf\fR procedure except for the following
- differences:
- .IP [1]
- \fB%p\fR and \fB%n\fR specifiers are not currently supported.
- .VE
- .IP [2]
- For \fB%c\fR conversions the argument must be a decimal string,
- which will then be converted to the corresponding character value.
- .IP [3]
- .VS
- The \fBl\fR modifier is ignored; integer values are always converted
- as if there were no modifier present and real values are always
- converted as if the \fBl\fR modifier were present (i.e. type
- \fBdouble\fR is used for the internal representation).
- If the \fBh\fR modifier is specified then integer values are truncated
- to \fBshort\fR before conversion.
- .VE
-
- .SH KEYWORDS
- conversion specifier, format, sprintf, string, substitution
-