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NAME |
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Guard - convert between different representations of perl |
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scalars |
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SYNOPSIS |
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use Guard; |
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DESCRIPTION |
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This module exports various internal perl methods that change the |
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internal representation or state of a perl scalar. All of these work |
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in-place, that is, they modify their scalar argument. No functions are |
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exported by default. |
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The following export tags exist: |
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:utf8 all functions with utf8 in their name |
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:taint all functions with taint in their name |
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:refcnt all functions with refcnt in their name |
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:ok all *ok-functions. |
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utf8 scalar[, mode] |
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Returns true when the given scalar is marked as utf8, false |
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otherwise. If the optional mode argument is given, also forces the |
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interpretation of the string to utf8 (mode true) or plain bytes |
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(mode false). The actual (byte-) content is not changed. The return |
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value always reflects the state before any modification is done. |
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This function is useful when you "import" utf8-data into perl, or |
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when some external function (e.g. storing/retrieving from a |
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database) removes the utf8-flag. |
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utf8_on scalar |
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Similar to "utf8 scalar, 1", but additionally returns the scalar |
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(the argument is still modified in-place). |
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utf8_off scalar |
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Similar to "utf8 scalar, 0", but additionally returns the scalar |
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(the argument is still modified in-place). |
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utf8_valid scalar [Perl 5.7] |
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Returns true if the bytes inside the scalar form a valid utf8 |
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string, false otherwise (the check is independent of the actual |
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encoding perl thinks the string is in). |
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utf8_upgrade scalar |
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Convert the string content of the scalar in-place to its |
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UTF8-encoded form (and also returns it). |
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utf8_downgrade scalar[, fail_ok=0] |
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Attempt to convert the string content of the scalar from |
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UTF8-encoded to ISO-8859-1. This may not be possible if the string |
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contains characters that cannot be represented in a single byte; if |
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this is the case, it leaves the scalar unchanged and either returns |
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false or, if "fail_ok" is not true (the default), croaks. |
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utf8_encode scalar |
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Convert the string value of the scalar to UTF8-encoded, but then |
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turn off the "SvUTF8" flag so that it looks like bytes to perl |
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again. (Might be removed in future versions). |
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utf8_length scalar |
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Returns the number of characters in the string, counting wide UTF8 |
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characters as a single character, independent of wether the scalar |
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is marked as containing bytes or mulitbyte characters. |
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unmagic scalar, type |
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Remove the specified magic from the scalar (DANGEROUS!). |
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weaken scalar |
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Weaken a reference. (See also WeakRef). |
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taint scalar |
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Taint the scalar. |
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tainted scalar |
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returns true when the scalar is tainted, false otherwise. |
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untaint scalar |
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Remove the tainted flag from the specified scalar. |
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grow scalar, newlen |
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Sets the memory area used for the scalar to the given length, if the |
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current length is less than the new value. This does not affect the |
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contents of the scalar, but is only useful to "pre-allocate" memory |
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space if you know the scalar will grow. The return value is the |
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modified scalar (the scalar is modified in-place). |
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refcnt scalar[, newrefcnt] |
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Returns the current reference count of the given scalar and |
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optionally sets it to the given reference count. |
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refcnt_inc scalar |
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Increments the reference count of the given scalar inplace. |
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refcnt_dec scalar |
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Decrements the reference count of the given scalar inplace. Use |
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"weaken" instead if you understand what this function is fore. |
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Better yet: don't use this module in this case. |
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refcnt_rv scalar[, newrefcnt] |
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Works like "refcnt", but dereferences the given reference first. |
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This is useful to find the reference count of arrays or hashes, |
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which cnanot be passed directly. Remember that taking a reference of |
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some object increases it's reference count, so the reference count |
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used by the *_rv-functions tend to be one higher. |
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refcnt_inc_rv scalar |
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Works like "refcnt_inc", but dereferences the given reference first. |
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refcnt_dec_rv scalar |
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Works like "refcnt_dec", but dereferences the given reference first. |
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ok scalar |
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uok scalar |
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rok scalar |
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pok scalar |
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nok scalar |
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niok scalar |
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Calls SvOK, SvUOK, SvROK, SvPOK, SvNOK or SvNIOK on the given |
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scalar, respectively. |
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CANDIDATES FOR FUTURE RELEASES |
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The following API functions (perlapi) are considered for future |
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inclusion in this module If you want them, write me. |
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sv_upgrade |
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sv_pvn_force |
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sv_pvutf8n_force |
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the sv2xx family |
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AUTHOR |
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Marc Lehmann <schmorp@schmorp.de> |
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http://home.schmorp.de/ |
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