How to return php extension error

How to set the error returned by the php extension: 1. Open the corresponding PHP file; 2. Throw an error prompt through the "php_error_docref()" function in the extension.

The operating environment of this article: windows7 system, PHP7.1 version, DELL G3 computer

How to return php extension error?

php source code - throwing and handling errors in extension

Let’s first talk about the types of errors at the source code level. There are probably the following types

//zend_errors.h 文件
#define E_ERROR             (1<<0L)
#define E_WARNING           (1<<1L)
#define E_PARSE             (1<<2L)
#define E_NOTICE            (1<<3L)
#define E_CORE_ERROR        (1<<4L)
#define E_CORE_WARNING      (1<<5L)
#define E_COMPILE_ERROR     (1<<6L)
#define E_COMPILE_WARNING   (1<<7L)
#define E_USER_ERROR        (1<<8L)
#define E_USER_WARNING      (1<<9L)
#define E_USER_NOTICE       (1<<10L)
#define E_STRICT            (1<<11L)
#define E_RECOVERABLE_ERROR (1<<12L)
#define E_DEPRECATED        (1<<13L)
#define E_USER_DEPRECATED   (1<<14L)

Among them, E_CORE_ERROR, E_ERROR, E_RECOVERABLE_ERROR, E_PARSE, E_COMPILE_ERROR, E_USER_ERROR. This error will trigger the try catch exception handling process, which will interrupt the execution of the current request. When this error occurs, the opcode currently to be executed will be set to ZEND_HANDLE_EXCEPTION, thus Jump out of program execution, specific jump out process reference: PHP source code - exception throw processing process -02

How do we throw error prompts when writing extensions?

Extension Error prompts can be thrown through the php_error_docref() function, such as

PHP_FUNCTION(academy_sample_fopen)
{
    FILE *fp;
    char *filename, *mode;
    int filename_len, mode_len;
    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss", &filename, &filename_len, &mode, &mode_len) == FAILURE)
    {
            RETURN_NULL();
    }
    if (!filename_len || !mode_len)
    {
           php_error_docref(NULL TSRMLS_CC, E_WARNING,"Invalid filename or mode length");
            RETURN_FALSE;
    }
    fp = fopen(filename, mode);
    if (!fp)
    {
        php_error_docref(NULL TSRMLS_CC, E_WARNING,"Unable to open %s using mode %s", filename, mode);
            RETURN_FALSE;
    }
}

This is the error prompt through php_error_docref. If triggered, the following error prompt output will appear

I believe it is writing I have seen similar error prompt output when writing PHP code.

PHP Fatal error:  Unknown: EEEEEEEEEEEEEEEEEEE in Unknown on line 0
PHP Warning:  Swoole\Php\Runner::run() expects exactly 4 parameters, 0 given in /var/www/swoole/http_test.php on line 22

How is this error prompt output achieved?

Follow up the source code of php_error_docref

//main/php.h
#define php_error_docref php_error_docref0
//main/main.c
PHPAPI ZEND_COLD void php_error_docref0(const char *docref, int type, const char *format, ...) 
{
    va_list args;
    va_start(args, format);
    php_verror(docref, "", type, format, args);
    va_end(args);
}
//main/main.c
PHPAPI ZEND_COLD void php_verror(const char *docref, const char *params, int type, const char *format, va_list args)
{
    php_error(type, "%s", message);
    efree(message);
}
//main/php.h
#define php_error zend_error
//Zend/zend.c
ZEND_API ZEND_COLD void zend_error(int type, const char *format, ...) /* {{{ */
{
    va_list va;
    va_start(va, format);
    zend_error_va_list(type, format, va);
    va_end(va);
}
static ZEND_COLD void zend_error_va_list(int type, const char *format, va_list args)
{
    if (EG(exception)) {
        switch (type) {
            case E_CORE_ERROR:
            case E_ERROR:
            case E_RECOVERABLE_ERROR:
            case E_PARSE:
            case E_COMPILE_ERROR:
            case E_USER_ERROR:
                                //严重错误，通过ZEND_HANDLE_EXCEPTION 中断程序
                if (ex && ex->opline->opcode == ZEND_HANDLE_EXCEPTION &&
                    EG(opline_before_exception)) {
                    opline = EG(opline_before_exception);
                }
                break;
        }
    }
      //...
   // zend_error_cb 很重要， 这个函数是在 sapi启动的时候，通过 php_module_startup() 赋值为 php_error_cb() 函数
   zend_error_cb(type, error_filename, error_lineno, format, args);
}

zend_error_cb is very important. This function is assigned to the php_error_cb() function through php_module_startup() when sapi starts, and php_error_cb() will eventually be called_ sapi_module_struct.log_message(), that is, when you call the php_error_docref() function to throw an error, _sapi_module_struct.log_message will actually be called back (refer to the specific execution process: php source code-custom error output in sapi), such as fpm sapi The error message will be returned to cli sapi by customizing this function to output the error message to the standard output

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