X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlrun.pod;h=c82e2804b15a9fbc98e0ea220876bf11b712c6ad;hb=03f3e794d79fbb3655a305de34b922dd4020d2ec;hp=b9737794371d8353189e0e03d083fd9c13597ab6;hpb=f23930d5bcecd13c3bde0f46942a01c0c8de4117;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perlrun.pod b/pod/perlrun.pod index b973779..c82e280 100644 --- a/pod/perlrun.pod +++ b/pod/perlrun.pod @@ -9,9 +9,7 @@ B S<[ B<-sTtuUWX> ]> S<[ B<-cw> ] [ B<-d>[B][:I] ] [ B<-D>[I] ]> S<[ B<-pna> ] [ B<-F>I ] [ B<-l>[I] ] [ B<-0>[I] ]> S<[ B<-I>I ] [ B<-m>[B<->]I ] [ B<-M>[B<->]I<'module...'> ] [ B<-f> ]> - S<[ B<-A>[I][=I] ]> S<[ B<-C [I] >]> - S<[ B<-P> ]> S<[ B<-S> ]> S<[ B<-x>[I] ]> S<[ B<-i>[I] ]> @@ -260,19 +258,6 @@ format: C<-0xHHH...>, where the C are valid hexadecimal digits. (This means that you cannot use the C<-x> with a directory name that consists of hexadecimal digits.) -=item B<-A[I][=I]> -X<-A> - -Activates the assertions given after the equal sign as a comma-separated -list of assertion names or regular expressions. If no assertion name -is given, activates all assertions. - -The module L is used by default to activate the -selected assertions. An alternate module may be specified including -its name between the switch and the equal sign. - -See L and L. - =item B<-a> X<-a> X @@ -294,7 +279,7 @@ An alternate delimiter may be specified using B<-F>. =item B<-C [I]> X<-C> -The C<-C> flag controls some Unicode of the Perl Unicode features. +The C<-C> flag controls some of the Perl Unicode features. As of 5.8.1, the C<-C> can be followed either by a number or a list of option letters. The letters, their numeric values, and effects @@ -314,6 +299,11 @@ are as follows; listing the letters is equal to summing the numbers. variables (the LC_ALL, LC_TYPE, and LANG, in the order of decreasing precedence) -- if the variables indicate UTF-8, then the selected "IOEioA" are in effect + a 256 Set ${^UTF8CACHE} to -1, to run the UTF-8 caching code in + debugging mode. + +=for documenting_the_underdocumented +perl.h gives W/128 as PERL_UNICODE_WIDESYSCALLS "/* for Sarathy */" =for todo perltodo mentions Unicode in %ENV and filenames. I guess that these will be @@ -355,10 +345,10 @@ switch was therefore "recycled".) X<-c> causes Perl to check the syntax of the program and then exit without -executing it. Actually, it I execute C, C, and -C blocks, because these are considered as occurring outside the -execution of your program. C and C blocks, however, will -be skipped. +executing it. Actually, it I execute C, C, +C, and C blocks, because these are considered as occurring +outside the execution of your program. C and C blocks, +however, will be skipped. =item B<-d> X<-d> X<-dt> @@ -404,13 +394,13 @@ B<-D14> is equivalent to B<-Dtls>): 8 t Trace execution 16 o Method and overloading resolution 32 c String/numeric conversions - 64 P Print profiling info, preprocessor command for -P, source file input state + 64 P Print profiling info, source file input state 128 m Memory allocation 256 f Format processing 512 r Regular expression parsing and execution 1024 x Syntax tree dump 2048 u Tainting checks - 4096 (Obsolete, previously used for LEAKTEST) + 4096 U Unofficial, User hacking (reserved for private, unreleased use) 8192 H Hash dump -- usurps values() 16384 X Scratchpad allocation 32768 D Cleaning up @@ -464,10 +454,10 @@ X<-f> Disable executing F<$Config{sitelib}/sitecustomize.pl> at startup. Perl can be built so that it by default will try to execute -F<$Config{sitelib}/sitecustomize.pl> at startup. This is a hook that -allows the sysadmin to customize how perl behaves. It can for -instance be used to add entries to the @INC array to make perl find -modules in non-standard locations. +F<$Config{sitelib}/sitecustomize.pl> at startup (in a BEGIN block). +This is a hook that allows the sysadmin to customize how perl behaves. +It can for instance be used to add entries to the @INC array to make perl +find modules in non-standard locations. =item B<-F>I X<-F> @@ -597,9 +587,7 @@ proceeds from STDIN to STDOUT as might be expected. X<-I> X<@INC> Directories specified by B<-I> are prepended to the search path for -modules (C<@INC>), and also tells the C preprocessor where to search for -include files. The C preprocessor is invoked with B<-P>; by default it -searches /usr/include and /usr/lib/perl. +modules (C<@INC>). =item B<-l>[I] X<-l> X<$/> X<$\> @@ -704,72 +692,6 @@ overrides a B<-n> switch. C and C blocks may be used to capture control before or after the implicit loop, just as in B. -=item B<-P> -X<-P> - -B - -This option causes your program to be run through the C preprocessor before -compilation by Perl. Because both comments and B directives begin -with the # character, you should avoid starting comments with any words -recognized by the C preprocessor such as C<"if">, C<"else">, or C<"define">. - -If you're considering using C<-P>, you might also want to look at the -Filter::cpp module from CPAN. - -The problems of -P include, but are not limited to: - -=over 10 - -=item * - -The C<#!> line is stripped, so any switches there don't apply. - -=item * - -A C<-P> on a C<#!> line doesn't work. - -=item * - -B lines that begin with (whitespace and) a C<#> but -do not look like cpp commands, are stripped, including anything -inside Perl strings, regular expressions, and here-docs . - -=item * - -In some platforms the C preprocessor knows too much: it knows about -the C++ -style until-end-of-line comments starting with C<"//">. -This will cause problems with common Perl constructs like - - s/foo//; - -because after -P this will became illegal code - - s/foo - -The workaround is to use some other quoting separator than C<"/">, -like for example C<"!">: - - s!foo!!; - - - -=item * - -It requires not only a working C preprocessor but also a working -F. If not on UNIX, you are probably out of luck on this. - -=item * - -Script line numbers are not preserved. - -=item * - -The C<-x> does not work with C<-P>. - -=back - =item B<-s> X<-s> @@ -878,10 +800,6 @@ execute a portion of your program before dumping, use the dump() operator instead. Note: availability of B is platform specific and may not be available for a specific port of Perl. -This switch has been superseded in favor of the new Perl code -generator backends to the compiler. See L and L -for details. - =item B<-U> X<-U> @@ -976,7 +894,7 @@ See L. =item B<-x> X<-x> -=item B<-x> I +=item B<-x>I tells Perl that the program is embedded in a larger chunk of unrelated ASCII text, such as in a mail message. Leading garbage will be @@ -989,6 +907,9 @@ C<__END__> if there is trailing garbage to be ignored (the program can process any or all of the trailing garbage via the DATA filehandle if desired). +The directory, if specified, must appear immediately following the B<-x> +with no intervening whitespace. + =back =head1 ENVIRONMENT @@ -1018,14 +939,17 @@ X A list of directories in which to look for Perl library files before looking in the standard library and the current directory. Any architecture-specific directories under the specified -locations are automatically included if they exist. If PERL5LIB is not -defined, PERLLIB is used. Directories are separated (like in PATH) by -a colon on unixish platforms and by a semicolon on Windows (the proper -path separator being given by the command C). +locations are automatically included if they exist (this lookup +being done at interpreter startup time.) + +If PERL5LIB is not defined, PERLLIB is used. Directories are separated +(like in PATH) by a colon on unixish platforms and by a semicolon on +Windows (the proper path separator being given by the command C). When running taint checks (either because the program was running setuid -or setgid, or the B<-T> switch was used), neither variable is used. -The program should instead say: +or setgid, or the B<-T> or B<-t> switch was specified), neither variable +is used. The program should instead say: use lib "/my/directory"; @@ -1033,7 +957,7 @@ The program should instead say: X Command-line options (switches). Switches in this variable are taken -as if they were on every Perl command line. Only the B<-[CDIMUdmtwA]> +as if they were on every Perl command line. Only the B<-[CDIMUdmtw]> switches are allowed. When running taint checks (because the program was running setuid or setgid, or the B<-T> switch was used), this variable is ignored. If PERL5OPT begins with B<-T>, tainting will be @@ -1050,7 +974,9 @@ emphasise their similarity to variable "attributes". But the code that parses layer specification strings (which is also used to decode the PERLIO environment variable) treats the colon as a separator. -An unset or empty PERLIO is equivalent to C<:stdio>. +An unset or empty PERLIO is equivalent to the default set of layers for +your platform, for example C<:unix:perlio> on UNIX-like systems +and C<:unix:crlf> on Windows and other DOS-like systems. The list becomes the default for I perl's IO. Consequently only built-in layers can appear in this list, as external layers (such as :encoding()) need @@ -1128,9 +1054,9 @@ X<:utf8> A pseudolayer that turns on a flag on the layer below to tell perl that output should be in utf8 and that input should be regarded as -already in utf8 form. May be useful in PERLIO environment -variable to make UTF-8 the default. (To turn off that behaviour -use C<:bytes> layer.) +already in valid utf8 form. It does not check for validity and as such +should be handled with caution for input. Generally C<:encoding(utf8)> is +the best option when reading UTF-8 encoded data. =item :win32 X<:win32> @@ -1262,20 +1188,23 @@ PERL_ENCODING environment variable is consulted for an encoding name. =item PERL_HASH_SEED X -(Since Perl 5.8.1.) Used to randomise Perl's internal hash function. +(Since Perl 5.8.1.) Used to randomise perl's internal hash function. To emulate the pre-5.8.1 behaviour, set to an integer (zero means exactly the same order as 5.8.0). "Pre-5.8.1" means, among other -things, that hash keys will be ordered the same between different runs -of Perl. +things, that hash keys will always have the same ordering between +different runs of perl. + +Most hashes return elements in the same order as Perl 5.8.0 by default. +On a hash by hash basis, if pathological data is detected during a hash +key insertion, then that hash will switch to an alternative random hash +seed. The default behaviour is to randomise unless the PERL_HASH_SEED is set. -If Perl has been compiled with C<-DUSE_HASH_SEED_EXPLICIT>, the default +If perl has been compiled with C<-DUSE_HASH_SEED_EXPLICIT>, the default behaviour is B to randomise unless the PERL_HASH_SEED is set. -If PERL_HASH_SEED is unset or set to a non-numeric string, Perl uses +If PERL_HASH_SEED is unset or set to a non-numeric string, perl uses the pseudorandom seed supplied by the operating system and libraries. -This means that each different run of Perl will have a different -ordering of the results of keys(), values(), and each(). B. Hashes are randomized to protect against local and remote attacks against Perl