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>PHP 手册</TH
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><A
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>章 46. Zend API：深入 PHP 内核</TD
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><DIV
CLASS="sect1"
><H1
CLASS="sect1"
><A
NAME="zend.printing"
>Printing Information</A
></H1
><P
> Often it's necessary to print messages to the output stream from
your module, just as <B
CLASS="function"
>print()</B
> would be used
within a script. PHP offers functions for most generic tasks, such
as printing warning messages, generating output for
<B
CLASS="function"
>phpinfo()</B
>, and so on. The following sections
provide more details. Examples of these functions can be found on
the CD-ROM.
</P
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="zendapi.printing.zend-printf"
><B
CLASS="function"
>zend_printf()</B
></A
></H2
><P
> <B
CLASS="function"
>zend_printf()</B
> works like the
standard <B
CLASS="function"
>printf()</B
>, except that it prints to Zend's
output stream.
</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="zend.printing.zend-error"
><A
HREF="zend-api.zend-error.html"
><B
CLASS="function"
>zend_error()</B
></A
></A
></H2
><P
> <A
HREF="zend-api.zend-error.html"
><B
CLASS="function"
>zend_error()</B
></A
> can be used to generate error messages.
This function accepts two arguments; the first is the error type (see
<TT
CLASS="filename"
>zend_errors.h</TT
>), and the second is the error message.
<TABLE
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><TR
><TD
><PRE
CLASS="programlisting"
>zend_error(E_WARNING, "This function has been called with empty arguments");</PRE
></TD
></TR
></TABLE
><A
HREF="zend.printing.html#tab.error-messages"
>表 46-16</A
> shows a list of possible values (see <A
HREF="zend.printing.html#fig.warning-messages"
>图 46-3</A
>). These
values are also referred to in <TT
CLASS="filename"
>php.ini</TT
>. Depending on
which error type you choose, your messages will be logged.
<DIV
CLASS="table"
><A
NAME="tab.error-messages"
></A
><P
><B
>表 46-16. Zend's Predefined Error Messages.</B
></P
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><COL
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TITLE="col2"><TBODY
><TR
><TD
>Error</TD
><TD
>Description</TD
></TR
><TR
><TD
><TT
CLASS="literal"
>E_ERROR</TT
></TD
><TD
> Signals an error and terminates execution of the script
immediately
.</TD
></TR
><TR
><TD
><TT
CLASS="literal"
>E_WARNING</TT
></TD
><TD
> Signals a generic warning. Execution continues.
</TD
></TR
><TR
><TD
><TT
CLASS="literal"
>E_PARSE</TT
></TD
><TD
> Signals a parser error. Execution continues.
</TD
></TR
><TR
><TD
><TT
CLASS="literal"
>E_NOTICE</TT
></TD
><TD
> Signals a notice. Execution continues. Note that by
default the display of this type of error messages is turned off in
<TT
CLASS="filename"
>php.ini</TT
>.
</TD
></TR
><TR
><TD
><TT
CLASS="literal"
>E_CORE_ERROR</TT
></TD
><TD
> Internal error by the core; shouldn't be used by
user-written modules.
</TD
></TR
><TR
><TD
><TT
CLASS="literal"
>E_COMPILE_ERROR</TT
></TD
><TD
> Internal error by the compiler; shouldn't be used by
user-written modules.
</TD
></TR
><TR
><TD
><TT
CLASS="literal"
>E_COMPILE_WARNING</TT
></TD
><TD
> Internal warning by the compiler; shouldn't be used by
user-written modules.
</TD
></TR
></TBODY
></TABLE
></DIV
>
<DIV
CLASS="figure"
><A
NAME="fig.warning-messages"
></A
><P
><B
>图 46-3. Display of warning messages in the browser.</B
></P
><P
><IMG
SRC="figures/zendapi.zend.07-warning-messages.png"></P
></DIV
></P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="zend.printing.phpinfo"
>Including Output in <B
CLASS="function"
>phpinfo()</B
></A
></H2
><P
> After creating a real module, you'll want to show information
about the module in <B
CLASS="function"
>phpinfo()</B
> (in addition to the
module name, which appears in the module list by default). PHP allows
you to create your own section in the <B
CLASS="function"
>phpinfo()</B
> output with the <TT
CLASS="literal"
>ZEND_MINFO()</TT
> function. This function
should be placed in the module descriptor block (discussed earlier) and is
always called whenever a script calls <B
CLASS="function"
>phpinfo()</B
>.
</P
><P
> PHP automatically prints a section
in <B
CLASS="function"
>phpinfo()</B
> for you if you specify the <TT
CLASS="literal"
>ZEND_MINFO</TT
>
function, including the module name in the heading. Everything else must be
formatted and printed by you.
</P
><P
> Typically, you can print an HTML table header
using <B
CLASS="function"
>php_info_print_table_start()</B
> and then use the standard
functions <B
CLASS="function"
>php_info_print_table_header()</B
>
and <B
CLASS="function"
>php_info_print_table_row()</B
>. As arguments, both take the number of
columns (as integers) and the column contents (as strings). <A
HREF="zend.printing.html#example.phpinfo"
>例 46-13</A
> shows a source example and its output. To print the table footer, use <B
CLASS="function"
>php_info_print_table_end()</B
>.
</P
><TABLE
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><TR
><TD
><DIV
CLASS="example"
><A
NAME="example.phpinfo"
></A
><P
><B
>例 46-13.
Source code and screenshot for output in <B
CLASS="function"
>phpinfo()</B
>.
</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="programlisting"
>php_info_print_table_start();
php_info_print_table_header(2, "First column", "Second column");
php_info_print_table_row(2, "Entry in first row", "Another entry");
php_info_print_table_row(2, "Just to fill", "another row here");
php_info_print_table_end();</PRE
></TD
></TR
></TABLE
><P
><IMG
SRC="figures/zendapi.zend.08-phpinfo-output.png"></P
></DIV
></TD
></TR
></TABLE
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="zend.printing.execution"
>Execution Information</A
></H2
><P
> You can also print execution information, such as the current file
being executed. The name of the function currently being executed
can be retrieved using the function
<A
HREF="zend-api.get-active-function-name.html"
><B
CLASS="function"
>get_active_function_name()</B
></A
>. This function
returns a pointer to the function name and doesn't accept any
arguments. To retrieve the name of the file currently being
executed, use <A
HREF="zend-api.zend-get-executed-filename.html"
><B
CLASS="function"
>zend_get_executed_filename()</B
></A
>.
This function accesses the executor globals, which are passed to
it using the <TT
CLASS="literal"
>TSRMLS_C</TT
> macro. The executor globals
are automatically available to every function that's called
directly by Zend (they're part of the
<TT
CLASS="literal"
>INTERNAL_FUNCTION_PARAMETERS</TT
> described earlier
in this chapter). If you want to access the executor globals in
another function that doesn't have them available automatically,
call the macro <TT
CLASS="literal"
>TSRMLS_FETCH()</TT
> once in that
function; this will introduce them to your local scope.
</P
><P
> Finally, the line number currently being executed can be retrieved
using the function <A
HREF="zend-api.zend-get-executed-lineno.html"
><B
CLASS="function"
>zend_get_executed_lineno()</B
></A
>.
This function also requires the executor globals as arguments. For
examples of these functions, see <A
HREF="zend.printing.html#example.exec-info"
>例 46-14</A
>.
</P
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><TR
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><DIV
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><A
NAME="example.exec-info"
></A
><P
><B
>例 46-14. Printing execution information.</B
></P
><TABLE
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><TR
><TD
><PRE
CLASS="programlisting"
>zend_printf("The name of the current function is %s<br>", get_active_function_name(TSRMLS_C));
zend_printf("The file currently executed is %s<br>", zend_get_executed_filename(TSRMLS_C));
zend_printf("The current line being executed is %i<br>", zend_get_executed_lineno(TSRMLS_C));</PRE
></TD
></TR
></TABLE
><P
><IMG
SRC="figures/zendapi.zend.09-execution-info.png"></P
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