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>Strings</H1
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>&#13;    Strings need slightly more effort. As mentioned earlier, all strings
    that will be associated with Zend's internal data structures need to be
    allocated using Zend's own memory-management functions. Referencing of static
    strings or strings allocated with standard routines is not allowed. To assign
    strings, you have to access the structure <TT
CLASS="envar"
>str</TT
> in
    the <TT
CLASS="envar"
>zval.value</TT
> container. The corresponding type
    is <TT
CLASS="literal"
>IS_STRING</TT
>:
<TABLE
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><TR
><TD
><PRE
CLASS="programlisting"
>zval *new_string;
char *string_contents = "This is a new string variable";

MAKE_STD_ZVAL(new_string);

new_string-&#62;type = IS_STRING;
new_string-&#62;value.str.len = strlen(string_contents);
new_string-&#62;value.str.val = estrdup(string_contents);</PRE
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>
    Note the usage of Zend's <B
CLASS="function"
>estrdup()</B
> here.
    Of course, you can also use the predefined macro
    <TT
CLASS="literal"
>ZVAL_STRING</TT
>:
    <TABLE
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><PRE
CLASS="programlisting"
>zval *new_string;
char *string_contents = "This is a new string variable";

MAKE_STD_ZVAL(new_string);
ZVAL_STRING(new_string, string_contents, 1);</PRE
></TD
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>
    <TT
CLASS="literal"
>ZVAL_STRING</TT
> accepts a third parameter that
    indicates whether the supplied string contents should be duplicated (using
    <B
CLASS="function"
>estrdup()</B
>). Setting this parameter
    to <TT
CLASS="literal"
>1</TT
> causes the string to be
    duplicated; <TT
CLASS="literal"
>0</TT
> simply uses the supplied pointer for the
    variable contents. This is most useful if you want to create a new variable
    referring to a string that's already allocated in Zend internal memory.
   </P
><P
>&#13;    If you want to truncate the string at a certain position or you
    already know its length, you can use <TT
CLASS="literal"
>ZVAL_STRINGL(zval,
     string, length, duplicate)</TT
>, which accepts an explicit
    string length to be set for the new string. This macro is faster
    than <TT
CLASS="literal"
>ZVAL_STRING</TT
> and also binary-safe.
   </P
><P
>&#13;    To create empty strings, set the string length to <TT
CLASS="literal"
>0</TT
> and
    use <TT
CLASS="literal"
>empty_string</TT
> as contents: 
    <TABLE
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><PRE
CLASS="programlisting"
>new_string-&#62;type = IS_STRING;
new_string-&#62;value.str.len = 0;
new_string-&#62;value.str.val = empty_string;</PRE
></TD
></TR
></TABLE
>
    Of course, there's a macro for this as
    well (<TT
CLASS="literal"
>ZVAL_EMPTY_STRING</TT
>):
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><PRE
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>MAKE_STD_ZVAL(new_string);
ZVAL_EMPTY_STRING(new_string);</PRE
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>
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