PHP函数的检查和错误

有一种方法可以在php中检查函数是否失败时使用“IF”

前

谢谢

看一看。不过，你必须在你的函数中加入它们

编辑：顺便说一句，如果您的函数不应该返回布尔值，那么如果出现问题，您可以让它返回false，并检查如下：

$result = getimagesize($image);

if ($result === false)
{
    //
}

看一看。不过，你必须在你的函数中加入它们

编辑：顺便说一句，如果您的函数不应该返回布尔值，那么如果出现问题，您可以让它返回false，并检查如下：

$result = getimagesize($image);

if ($result === false)
{
    //
}

---

无论“if”语句的条件是什么（括号内的内容），都将返回“true”或“false”。 如果条件返回“true”，将执行第一条语句，否则将执行第二条语句

你可以把这个，错误报告（全部）；在脚本的最顶端，在打开php标记之后，查看得到的错误

希望能有帮助

也许是这样的：

<?php
error_reporting(E_ALL);
more stuff here ...
if(your condition here){
echo "condition is true, do something";
}else{
echo "condition is not true, do something else";
}

// Set our own error handler; we will restore the default one afterwards.
// Our new error handler need only handle E_WARNING and E_NOTICE, as per
// the documentation of getimagesize().
set_error_handler("my_error_handler", E_WARNING | E_NOTICE);

// No error has occured yet; it is the responsibility of my_error_handler
// to set $error_occurred to true if an error occurs.
$error_occurred = false; 

// Call getimagesize; use operator @ to have errors not be generated
// However, your error handler WILL STILL BE CALLED, as the documentation
// for set_error_handler() states.
$size = @getimagesize(...);

// At this point, my_error_handler will have run if an error occurred, and
// $error_occurred will be true. Before doing anything with it, restore the
// previous error handler
restore_error_handler();

if($error_occurred) {
    // whatever
}
else {
    // no error; $size holds information we can use
}


function my_error_handler($errno, $errstr, $file, $line) {
    global $error_occurred;

    // If the code is written as above, then we KNOW that an error
    // here was caused by getimagesize(). We also know what error it was:
    switch($errno) {
        case E_WARNING: // Access to image impossible, or not a valid picture
        case E_NOTICE:  // Read error
    }

    // We could also check what $file is and maybe do something based on that,
    // if this error handler is used from multiple places. However, I would not
    // recommend that. If you need more functionality, just package all of this
    // into a class and use the objects of that class to store more state.

    $error_occurred = true;
    return true; // Do not let PHP's default error handler handle this after us
}

---

无论“if”语句的条件是什么（括号内的内容），都将返回“true”或“false”。
如果条件返回“true”，将执行第一条语句，否则将执行第二条语句

你可以把这个，错误报告（全部）；在脚本的最顶端，在打开php标记之后，查看得到的错误

希望能有帮助

也许是这样的：

<?php
error_reporting(E_ALL);
more stuff here ...
if(your condition here){
echo "condition is true, do something";
}else{
echo "condition is not true, do something else";
}

// Set our own error handler; we will restore the default one afterwards.
// Our new error handler need only handle E_WARNING and E_NOTICE, as per
// the documentation of getimagesize().
set_error_handler("my_error_handler", E_WARNING | E_NOTICE);

// No error has occured yet; it is the responsibility of my_error_handler
// to set $error_occurred to true if an error occurs.
$error_occurred = false; 

// Call getimagesize; use operator @ to have errors not be generated
// However, your error handler WILL STILL BE CALLED, as the documentation
// for set_error_handler() states.
$size = @getimagesize(...);

// At this point, my_error_handler will have run if an error occurred, and
// $error_occurred will be true. Before doing anything with it, restore the
// previous error handler
restore_error_handler();

if($error_occurred) {
    // whatever
}
else {
    // no error; $size holds information we can use
}


function my_error_handler($errno, $errstr, $file, $line) {
    global $error_occurred;

    // If the code is written as above, then we KNOW that an error
    // here was caused by getimagesize(). We also know what error it was:
    switch($errno) {
        case E_WARNING: // Access to image impossible, or not a valid picture
        case E_NOTICE:  // Read error
    }

    // We could also check what $file is and maybe do something based on that,
    // if this error handler is used from multiple places. However, I would not
    // recommend that. If you need more functionality, just package all of this
    // into a class and use the objects of that class to store more state.

    $error_occurred = true;
    return true; // Do not let PHP's default error handler handle this after us
}

我假设您对像
getimagesize
这样的函数特别感兴趣，它不会返回任何错误代码，这对我们来说很困难。但并非不可能

getimagesize
的文档说明：

如果无法访问文件名图像，或者它不是有效的图片，
getimagesize（）
将生成级别为
E\u警告的错误。读取错误时，
getimagesize（）
将生成级别为
E\u NOTICE
的错误

因此，您需要做两件事：

得到错误的通知并以某种方式采取行动
不要显示错误或以其他方式影响程序的执行（毕竟，您将自己处理错误处理代码中的任何错误）
您可以使用和实现第一个。您可以使用
@
实现第二个

因此，代码必须是这样的：

<?php
error_reporting(E_ALL);
more stuff here ...
if(your condition here){
echo "condition is true, do something";
}else{
echo "condition is not true, do something else";
}

// Set our own error handler; we will restore the default one afterwards.
// Our new error handler need only handle E_WARNING and E_NOTICE, as per
// the documentation of getimagesize().
set_error_handler("my_error_handler", E_WARNING | E_NOTICE);

// No error has occured yet; it is the responsibility of my_error_handler
// to set $error_occurred to true if an error occurs.
$error_occurred = false; 

// Call getimagesize; use operator @ to have errors not be generated
// However, your error handler WILL STILL BE CALLED, as the documentation
// for set_error_handler() states.
$size = @getimagesize(...);

// At this point, my_error_handler will have run if an error occurred, and
// $error_occurred will be true. Before doing anything with it, restore the
// previous error handler
restore_error_handler();

if($error_occurred) {
    // whatever
}
else {
    // no error; $size holds information we can use
}


function my_error_handler($errno, $errstr, $file, $line) {
    global $error_occurred;

    // If the code is written as above, then we KNOW that an error
    // here was caused by getimagesize(). We also know what error it was:
    switch($errno) {
        case E_WARNING: // Access to image impossible, or not a valid picture
        case E_NOTICE:  // Read error
    }

    // We could also check what $file is and maybe do something based on that,
    // if this error handler is used from multiple places. However, I would not
    // recommend that. If you need more functionality, just package all of this
    // into a class and use the objects of that class to store more state.

    $error_occurred = true;
    return true; // Do not let PHP's default error handler handle this after us
}

当然，这不是很容易维护的（您在那里有一个全局变量
$error\u，这不是一个好的做法）。因此，对于一个不仅有效而且设计精良的解决方案，您可以将所有这些都打包到一个类中。该类将定义：

实现错误处理程序的方法（
my\u error\u handler
，在上面的示例中）。要将对象方法设置为错误处理程序而不是全局函数，需要使用合适的第一个参数调用
set\u error\u handler
；看
该方法允许类设置错误处理程序，执行您选择的一些代码，保存“执行代码时出错”标志，并还原错误处理程序。例如，此方法可以获取调用代码提供的
回调
，以及一组参数，并用于执行它。如果在执行过程中调用了上面#1中的错误处理程序集，请在对象的变量中标记该错误处理程序集。您的方法将
call\u user\u func\u array
的返回值返回给调用代码
调用代码可用于访问上述#2结果的方法或变量
因此，如果该类被称为ErrorWatcher，则调用代码如下：

$watcher = new ErrorWatcher;
$size = $watcher->watch("getimagesize",
                        array( /* params for getimagesize here */ ));

// $size holds your result, if an error did not occur;
// check for errors and we 're done!

switch($watcher->report_last_error()) {
    // error handling logic here
}

…这是好的和整洁的，不会弄乱全局变量。我希望我对这一点解释得足够好，使您能够自己编写类ErrorWatcher.：-）
 我假设您对像
getimagesize
这样的函数特别感兴趣，它不会返回任何错误代码，这对我们来说很困难。但并非不可能

getimagesize
的文档说明：

如果无法访问文件名图像，或者它不是有效的图片，
getimagesize（）
将生成级别为
E\u警告的错误。读取错误时，
getimagesize（）
将生成级别为
E\u NOTICE
的错误

因此，您需要做两件事：

得到错误的通知并以某种方式采取行动
不要显示错误或以其他方式影响程序的执行（毕竟，您将自己处理错误处理代码中的任何错误）
您可以使用和实现第一个。您可以使用
@
实现第二个

因此，代码必须是这样的：

<?php
error_reporting(E_ALL);
more stuff here ...
if(your condition here){
echo "condition is true, do something";
}else{
echo "condition is not true, do something else";
}

// Set our own error handler; we will restore the default one afterwards.
// Our new error handler need only handle E_WARNING and E_NOTICE, as per
// the documentation of getimagesize().
set_error_handler("my_error_handler", E_WARNING | E_NOTICE);

// No error has occured yet; it is the responsibility of my_error_handler
// to set $error_occurred to true if an error occurs.
$error_occurred = false; 

// Call getimagesize; use operator @ to have errors not be generated
// However, your error handler WILL STILL BE CALLED, as the documentation
// for set_error_handler() states.
$size = @getimagesize(...);

// At this point, my_error_handler will have run if an error occurred, and
// $error_occurred will be true. Before doing anything with it, restore the
// previous error handler
restore_error_handler();

if($error_occurred) {
    // whatever
}
else {
    // no error; $size holds information we can use
}


function my_error_handler($errno, $errstr, $file, $line) {
    global $error_occurred;

    // If the code is written as above, then we KNOW that an error
    // here was caused by getimagesize(). We also know what error it was:
    switch($errno) {
        case E_WARNING: // Access to image impossible, or not a valid picture
        case E_NOTICE:  // Read error
    }

    // We could also check what $file is and maybe do something based on that,
    // if this error handler is used from multiple places. However, I would not
    // recommend that. If you need more functionality, just package all of this
    // into a class and use the objects of that class to store more state.

    $error_occurred = true;
    return true; // Do not let PHP's default error handler handle this after us
}

当然，这不是很容易维护的（您在那里有一个全局变量
$error\u，这不是一个好的做法）。因此，对于一个不仅有效而且设计精良的解决方案，您可以将所有这些都打包到一个类中。该类将定义：

实现错误处理程序的方法（
my\u error\u handler
，在上面的示例中）。要将对象方法设置为错误处理程序而不是全局函数，需要使用合适的第一个参数调用
set\u error\u handler
；看
该方法允许类设置错误处理程序，执行您选择的一些代码，保存“执行代码时出错”标志，并还原错误处理程序。例如，此方法可以获取调用代码提供的
回调
，以及一组参数，并用于执行它。如果在执行过程中调用了上面#1中的错误处理程序集，请在对象的变量中标记该错误处理程序集。您的方法将
call\u user\u func\u array
的返回值返回给调用代码
一种方法或变量