CHAPTER 15 - Writing Your First Resource-Enabled PHP Function

Implementing
file_open() should now be easy, and it should look as follows:
PHP_FUNCTION(file_open)
{
char *filename = NULL;
char *mode = NULL;
int argc = ZEND_NUM_ARGS();
int filename_len;
int mode_len;
FILE *fp;
if (zend_parse_parameters(argc TSRMLS_CC, “ss”, &filename,
&filename_len, &mode, &mode_len) == FAILURE) {
return;
}
fp = VCWD_FOPEN(filename, mode);
if (fp == NULL) {
RETURN_FALSE;
}
ZEND_REGISTER_RESOURCE(return_value, fp, le_myfile);
}
You might notice that the first argument to the resource registration
macro is a variable called return_value, which has appeared out of nowhere.
This variable is automatically defined by the extension framework and is a
zval * to the function’s return value. The previously discussed macros, which
affect the return value such as RETURN_LONG() and RETVAL_BOOL(), actually
change the value of return_value. Therefore, it is easy to guess that the code
registers our acquired file pointer fp and sets the return_value to the regis-
tered resource.