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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:43:11 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:43:11 +0000 |
commit | fc22b3d6507c6745911b9dfcc68f1e665ae13dbc (patch) | |
tree | ce1e3bce06471410239a6f41282e328770aa404a /upstream/debian-unstable/man3/autouse.3perl | |
parent | Initial commit. (diff) | |
download | manpages-l10n-fc22b3d6507c6745911b9dfcc68f1e665ae13dbc.tar.xz manpages-l10n-fc22b3d6507c6745911b9dfcc68f1e665ae13dbc.zip |
Adding upstream version 4.22.0.upstream/4.22.0
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'upstream/debian-unstable/man3/autouse.3perl')
-rw-r--r-- | upstream/debian-unstable/man3/autouse.3perl | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/upstream/debian-unstable/man3/autouse.3perl b/upstream/debian-unstable/man3/autouse.3perl new file mode 100644 index 00000000..8e3dd8eb --- /dev/null +++ b/upstream/debian-unstable/man3/autouse.3perl @@ -0,0 +1,126 @@ +.\" -*- 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 "autouse 3perl" +.TH autouse 3perl 2024-01-12 "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 +autouse \- postpone load of modules until a function is used +.SH SYNOPSIS +.IX Header "SYNOPSIS" +.Vb 2 +\& use autouse \*(AqCarp\*(Aq => qw(carp croak); +\& carp "this carp was predeclared and autoused "; +.Ve +.SH DESCRIPTION +.IX Header "DESCRIPTION" +If the module \f(CW\*(C`Module\*(C'\fR is already loaded, then the declaration +.PP +.Vb 1 +\& use autouse \*(AqModule\*(Aq => qw(func1 func2($;$)); +.Ve +.PP +is equivalent to +.PP +.Vb 1 +\& use Module qw(func1 func2); +.Ve +.PP +if \f(CW\*(C`Module\*(C'\fR defines \fBfunc2()\fR with prototype \f(CW\*(C`($;$)\*(C'\fR, and \fBfunc1()\fR has +no prototypes. (At least if \f(CW\*(C`Module\*(C'\fR uses \f(CW\*(C`Exporter\*(C'\fR's \f(CW\*(C`import\*(C'\fR, +otherwise it is a fatal error.) +.PP +If the module \f(CW\*(C`Module\*(C'\fR is not loaded yet, then the above declaration +declares functions \fBfunc1()\fR and \fBfunc2()\fR in the current package. When +these functions are called, they load the package \f(CW\*(C`Module\*(C'\fR if needed, +and substitute themselves with the correct definitions. +.SH WARNING +.IX Header "WARNING" +Using \f(CW\*(C`autouse\*(C'\fR will move important steps of your program's execution +from compile time to runtime. This can +.IP \(bu 4 +Break the execution of your program if the module you \f(CW\*(C`autouse\*(C'\fRd has +some initialization which it expects to be done early. +.IP \(bu 4 +hide bugs in your code since important checks (like correctness of +prototypes) is moved from compile time to runtime. In particular, if +the prototype you specified on \f(CW\*(C`autouse\*(C'\fR line is wrong, you will not +find it out until the corresponding function is executed. This will be +very unfortunate for functions which are not always called (note that +for such functions \f(CW\*(C`autouse\*(C'\fRing gives biggest win, for a workaround +see below). +.PP +To alleviate the second problem (partially) it is advised to write +your scripts like this: +.PP +.Vb 3 +\& use Module; +\& use autouse Module => qw(carp($) croak(&$)); +\& carp "this carp was predeclared and autoused "; +.Ve +.PP +The first line ensures that the errors in your argument specification +are found early. When you ship your application you should comment +out the first line, since it makes the second one useless. +.SH AUTHOR +.IX Header "AUTHOR" +Ilya Zakharevich (ilya@math.ohio\-state.edu) +.SH "SEE ALSO" +.IX Header "SEE ALSO" +\&\fBperl\fR\|(1). |