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Diffstat (limited to 'upstream/archlinux/man3/integer.3perl')
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diff --git a/upstream/archlinux/man3/integer.3perl b/upstream/archlinux/man3/integer.3perl new file mode 100644 index 00000000..8b42e5f4 --- /dev/null +++ b/upstream/archlinux/man3/integer.3perl @@ -0,0 +1,142 @@ +.\" -*- mode: troff; coding: utf-8 -*- +.\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) +.\" +.\" Standard preamble: +.\" ======================================================================== +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.de Vb \" Begin verbatim text +.ft CW +.nf +.ne \\$1 +.. +.de Ve \" End verbatim text +.ft R +.fi +.. +.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. +.ie n \{\ +. ds C` "" +. ds C' "" +'br\} +.el\{\ +. ds C` +. ds C' +'br\} +.\" +.\" Escape single quotes in literal strings from groff's Unicode transform. +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" +.\" If the F register is >0, we'll generate index entries on stderr for +.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index +.\" entries marked with X<> in POD. Of course, you'll have to process the +.\" output yourself in some meaningful fashion. +.\" +.\" Avoid warning from groff about undefined register 'F'. +.de IX +.. +.nr rF 0 +.if \n(.g .if rF .nr rF 1 +.if (\n(rF:(\n(.g==0)) \{\ +. if \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" +.. +. if !\nF==2 \{\ +. nr % 0 +. nr F 2 +. \} +. \} +.\} +.rr rF +.\" ======================================================================== +.\" +.IX Title "integer 3perl" +.TH integer 3perl 2024-02-11 "perl v5.38.2" "Perl Programmers Reference Guide" +.\" For nroff, turn off justification. Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.if n .ad l +.nh +.SH NAME +integer \- Perl pragma to use integer arithmetic instead of floating point +.SH SYNOPSIS +.IX Header "SYNOPSIS" +.Vb 3 +\& use integer; +\& $x = 10/3; +\& # $x is now 3, not 3.33333333333333333 +.Ve +.SH DESCRIPTION +.IX Header "DESCRIPTION" +This tells the compiler to use integer operations from here to the end +of the enclosing BLOCK. On many machines, this doesn't matter a great +deal for most computations, but on those without floating point +hardware, it can make a big difference in performance. +.PP +Note that this only affects how most of the arithmetic and relational +\&\fBoperators\fR handle their operands and results, and \fBnot\fR how all +numbers everywhere are treated. Specifically, \f(CW\*(C`use integer;\*(C'\fR has the +effect that before computing the results of the arithmetic operators +(+, \-, *, /, %, +=, \-=, *=, /=, %=, and unary minus), the comparison +operators (<, <=, >, >=, ==, !=, <=>), and the bitwise operators (|, &, +^, <<, >>, |=, &=, ^=, <<=, >>=), the operands have their fractional +portions truncated (or floored), and the result will have its +fractional portion truncated as well. In addition, the range of +operands and results is restricted to that of familiar two's complement +integers, i.e., \-(2**31) .. (2**31\-1) on 32\-bit architectures, and +\&\-(2**63) .. (2**63\-1) on 64\-bit architectures. For example, this code +.PP +.Vb 7 +\& use integer; +\& $x = 5.8; +\& $y = 2.5; +\& $z = 2.7; +\& $a = 2**31 \- 1; # Largest positive integer on 32\-bit machines +\& $, = ", "; +\& print $x, \-$x, $x+$y, $x\-$y, $x/$y, $x*$y, $y==$z, $a, $a+1; +.Ve +.PP +will print: 5.8, \-5, 7, 3, 2, 10, 1, 2147483647, \-2147483648 +.PP +Note that \f(CW$x\fR is still printed as having its true non-integer value of +5.8 since it wasn't operated on. And note too the wrap-around from the +largest positive integer to the largest negative one. Also, arguments +passed to functions and the values returned by them are \fBnot\fR affected +by \f(CW\*(C`use integer;\*(C'\fR. E.g., +.PP +.Vb 3 +\& srand(1.5); +\& $, = ", "; +\& print sin(.5), cos(.5), atan2(1,2), sqrt(2), rand(10); +.Ve +.PP +will give the same result with or without \f(CW\*(C`use integer;\*(C'\fR The power +operator \f(CW\*(C`**\*(C'\fR is also not affected, so that 2 ** .5 is always the +square root of 2. Now, it so happens that the pre\- and post\- increment +and decrement operators, ++ and \-\-, are not affected by \f(CW\*(C`use integer;\*(C'\fR +either. Some may rightly consider this to be a bug \-\- but at least it's +a long-standing one. +.PP +Finally, \f(CW\*(C`use integer;\*(C'\fR also has an additional affect on the bitwise +operators. Normally, the operands and results are treated as +\&\fBunsigned\fR integers, but with \f(CW\*(C`use integer;\*(C'\fR the operands and results +are \fBsigned\fR. This means, among other things, that ~0 is \-1, and \-2 & +\&\-5 is \-6. +.PP +Internally, native integer arithmetic (as provided by your C compiler) +is used. This means that Perl's own semantics for arithmetic +operations may not be preserved. One common source of trouble is the +modulus of negative numbers, which Perl does one way, but your hardware +may do another. +.PP +.Vb 4 +\& % perl \-le \*(Aqprint (4 % \-3)\*(Aq +\& \-2 +\& % perl \-Minteger \-le \*(Aqprint (4 % \-3)\*(Aq +\& 1 +.Ve +.PP +See "Pragmatic Modules" in perlmodlib, "Integer Arithmetic" in perlop |