X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlvar.pod;h=15308e45aab4d907c005394eba798f3fc82af34d;hb=db22727b1cdf038cfb2d069831d76310ffc4b838;hp=28842efa5b652bbf60d651db2a7704e078d5e322;hpb=46487f74b15c77c6f040c8b818f810a5255b1078;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perlvar.pod b/pod/perlvar.pod index 28842ef..15308e4 100644 --- a/pod/perlvar.pod +++ b/pod/perlvar.pod @@ -99,7 +99,7 @@ The implicit iterator variable in the grep() and map() functions. =item * -The default place to put an input record when a CFHE> +The default place to put an input record when a C<< >> operation's result is tested by itself as the sole criterion of a C test. Outside a C test, this will not happen. @@ -111,7 +111,7 @@ test. Outside a C test, this will not happen. =over 8 -=item $EIE +=item $> Contains the subpattern from the corresponding set of capturing parentheses from the last pattern match, not counting patterns @@ -174,18 +174,20 @@ example: (Mnemonic: be positive and forward looking.) This variable is read-only and dynamically scoped to the current BLOCK. +=item @LAST_MATCH_END + =item @+ -$+[0] is the offset of the end of the last successful match. -C<$+[>IC<]> is the offset of the end of the substring matched by -I-th subpattern, or undef if the subpattern did not match. - -Thus after a match against $_, $& coincides with C. Similarly, C<$>I coincides with CIC<], -$+[>IC<] - $-[>IC<]> if C<$-[>IC<]> is defined, and $+ coincides with -C. One can use C<$#+> to find the number -of subgroups in the last successful match. Contrast with -C<$#E<45>>, the last I subgroup. Compare with C<@E<45>>. +This array holds the offsets of the ends of the last successful +submatches in the currently active dynamic scope. C<$+[0]> is +the offset into the string of the end of the entire match. This +is the same value as what the C function returns when called +on the variable that was matched against. The Ith element +of this array holds the offset of the Ith submatch, so +C<$+[1]> is the offset past where $1 ends, C<$+[2]> the offset +past where $2 ends, and so on. You can use C<$#+> to determine +how many subgroups were in the last successful match. See the +examples given for the C<@-> variable. =item $MULTILINE_MATCHING @@ -215,7 +217,7 @@ you just read() (or called a C or C on). The value may be different from the actual physical line number in the file, depending on what notion of "line" is in effect--see C<$/> on how to change that. An explicit close on a filehandle resets the line -number. Because CE> never does an explicit close, line +number. Because C<< <> >> never does an explicit close, line numbers increase across ARGV files (but see examples in L). Consider this variable read-only: setting it does not reposition the seek pointer; you'll have to do that on your own. Localizing C<$.> @@ -412,6 +414,8 @@ channel. Used with formats. (Mnemonic: lines_on_page - lines_printed.) +=item @LAST_MATCH_START + =item @- $-[0] is the offset of the start of the last successful match. @@ -421,11 +425,38 @@ I-th subpattern, or undef if the subpattern did not match. Thus after a match against $_, $& coincides with C. Similarly, C<$>I coincides with CIC<], $+[>IC<] - $-[>IC<]> if C<$-[>IC<]> is defined, and $+ coincides with -C. One can use C<$#E<45>> to find the last +C. One can use C<$#-> to find the last matched subgroup in the last successful match. Contrast with C<$#+>, the number of subgroups in the regular expression. Compare with C<@+>. +This array holds the offsets of the beginnings of the last +successful submatches in the currently active dynamic scope. +C<$-[0]> is the offset into the string of the beginning of the +entire match. The Ith element of this array holds the offset +of the Ith submatch, so C<$+[1]> is the offset where $1 +begins, C<$+[2]> the offset where $2 begins, and so on. +You can use C<$#-> to determine how many subgroups were in the +last successful match. Compare with the C<@+> variable. + +After a match against some variable $var: + +=over 5 + +=item C<$`> is the same as C + +=item C<$&> is the same as C + +=item C<$'> is the same as C + +=item C<$1> is the same as C + +=item C<$2> is the same as C + +=item C<$3> is the same as C + +=back + =item format_name HANDLE EXPR =item $FORMAT_NAME @@ -484,7 +515,7 @@ The status returned by the last pipe close, backtick (C<``>) command, successful call to wait() or waitpid(), or from the system() operator. This is just the 16-bit status word returned by the wait() system call (or else is made up to look like it). Thus, the -exit value of the subprocess is really (C<$? EE 8>), and +exit value of the subprocess is really (C<<< $? >> 8 >>>), and C<$? & 127> gives which signal, if any, the process died from, and C<$? & 128> reports whether there was a core dump. (Mnemonic: similar to B and B.) @@ -602,7 +633,7 @@ The effective uid of this process. Example: ($<,$>) = ($>,$<); # swap real and effective uid (Mnemonic: it's the uid you went I, if you're running setuid.) -C<$E> and C<$E> can be swapped only on machines +C<< $< >> and C<< $> >> can be swapped only on machines supporting setreuid(). =item $REAL_GROUP_ID @@ -646,7 +677,7 @@ list, say C< $) = "5 5" >. (Mnemonic: parentheses are used to I things. The effective gid is the group that's I for you, if you're running setgid.) -C<$E>, C<$E>, C<$(> and C<$)> can be set only on +C<< $< >>, C<< $> >>, C<$(> and C<$)> can be set only on machines that support the corresponding I routine. C<$(> and C<$)> can be swapped only on machines supporting setregid(). @@ -672,8 +703,6 @@ As of release 5 of Perl, assignment to C<$[> is treated as a compiler directive, and cannot influence the behavior of any other file. Its use is highly discouraged. -=item $PERL_VERSION - =item $] The version + patchlevel / 1000 of the Perl interpreter. This variable @@ -686,7 +715,10 @@ of perl in the right bracket?) Example: See also the documentation of C and C for a convenient way to fail if the running Perl interpreter is too old. -See C<$^V> for a more modern representation of the Perl version. +The use of this variable is deprecated. The floating point representation +can sometimes lead to inaccurate numeric comparisons. See C<$^V> for a +more modern representation of the Perl version that allows accurate string +comparisons. =item $COMPILING @@ -715,7 +747,8 @@ descriptors are not. Also, during an open(), system file descriptors are preserved even if the open() fails. (Ordinary file descriptors are closed before the open() is attempted.) The close-on-exec status of a file descriptor will be decided according to the value of -C<$^F> when the open() or pipe() was called, not the time of the exec(). +C<$^F> when the corresponding file, pipe, or socket was opened, not the +time of the exec(). =item $^H @@ -785,7 +818,7 @@ Then $^M = 'a' x (1 << 16); -would allocate a 64K buffer for use when in emergency. See the +would allocate a 64K buffer for use in an emergency. See the F file in the Perl distribution for information on how to enable this option. To discourage casual use of this advanced feature, there is no L long name for this variable. @@ -854,11 +887,15 @@ were compiled. Some bits may be relevant at compile-time only, some at run-time only. This is a new mechanism and the details may change. +=item $LAST_REGEXP_CODE_RESULT + =item $^R The result of evaluation of the last successful C<(?{ code })> regular expression assertion (see L). May be written to. +=item $EXCEPTIONS_BEING_CAUGHT + =item $^S Current state of the interpreter. Undefined if parsing of the current @@ -873,22 +910,23 @@ The time at which the program began running, in seconds since the epoch (beginning of 1970). The values returned by the B<-M>, B<-A>, and B<-C> filetests are based on this value. +=item $PERL_VERSION + =item $^V The revision, version, and subversion of the Perl interpreter, represented -as a "version tuple". Version tuples have both a numeric value and a -string value. The numeric value is a floating point number that amounts -to revision + version/1000 + subversion/1000000, and the string value -is made of characters possibly in the UTF-8 range: -C. +as a string composed of characters with those ordinals. Thus in Perl v5.6.0 +it equals C and will return true for +C<$^V eq v5.6.0>. Note that the characters in this string value can +potentially be in Unicode range. This can be used to determine whether the Perl interpreter executing a script is in the right range of versions. (Mnemonic: use ^V for Version -control.) Example: +Control.) Example: - warn "No "our" declarations!\n" if $^V and $^V lt v5.6; + warn "No "our" declarations!\n" if $^V and $^V lt v5.6.0; -See also the documentation of C and C +See the documentation of C and C for a convenient way to fail if the running Perl interpreter is too old. See also C<$]> for an older representation of the Perl version. @@ -918,8 +956,8 @@ The initial value is typically C<0> for compatibility with Perl versions earlier than 5.6, but may be automatically set to C<1> by Perl if the system provides a user-settable default (e.g., C<$ENV{LC_CTYPE}>). -The C pragma always overrides the effect of this flag in the current -lexical scope. See L. +The C pragma always overrides the effect of this flag in the current +lexical scope. See L. =item $EXECUTABLE_NAME @@ -930,7 +968,7 @@ This may not be a full pathname, nor even necessarily in your path. =item $ARGV -contains the name of the current file when reading from EE. +contains the name of the current file when reading from <>. =item @ARGV @@ -1100,7 +1138,7 @@ the value of $@ is the compile error, or the argument to C (which will interpolate C<$!> and C<$?>!). (See also L, though.) -When the eval() expression above is executed, open(), C<>, +When the eval() expression above is executed, open(), C<< >>, and C are translated to calls in the C run-time library and thence to the operating system kernel. C<$!> is set to the C library's C if one of these calls fails. @@ -1177,7 +1215,7 @@ expression matches in a program, regardless of whether they occur in the scope of C. For that reason, saying C in libraries is strongly discouraged. See the Devel::SawAmpersand module documentation from CPAN -(http://www.perl.com/CPAN/modules/by-module/Devel/Devel-SawAmpersand-0.10.readme) +(http://www.perl.com/CPAN/modules/by-module/Devel/) for more information. Having to even think about the C<$^S> variable in your exception