Difference between set_time_limit() and ini_set('max_execution_time', ...)

Question

Is there any actual difference between these two lines of code?

ini_set('max_execution_time', 20*60); set_time_limit(20*60); 

Answer 1

Looking at the current source:

/* {{{ proto bool set_time_limit(int seconds)    Sets the maximum time a script can run */ PHP_FUNCTION(set_time_limit) {     zend_long new_timeout;     char *new_timeout_str;     int new_timeout_strlen;     zend_string *key;      if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &new_timeout) == FAILURE) {         return;     }      new_timeout_strlen = zend_spprintf(&new_timeout_str, 0, ZEND_LONG_FMT, new_timeout);      key = zend_string_init("max_execution_time", sizeof("max_execution_time")-1, 0);     if (zend_alter_ini_entry_chars_ex(key, new_timeout_str, new_timeout_strlen, PHP_INI_USER, PHP_INI_STAGE_RUNTIME, 0 TSRMLS_CC) == SUCCESS) {         RETVAL_TRUE;     } else {         RETVAL_FALSE;     }     zend_string_release(key);     efree(new_timeout_str); } /* }}} */ 

set_time_limit() is indeed just a convenience wrapper around the according ini_set() call. It doesn't even seem to perform the advertised timer reset. (But I would guess the "timer" actually isn't a separate entity, but the ini value itself is used as such.)

Answer 2

A tiny difference to take into account is the way they behave on failure:

• set_time_limit() does not return anything so you can't use it to detect whether it succeeded. Additionally, it'll throw a warning:

  Warning: set_time_limit(): Cannot set time limit in safe mode

• ini_set() returns FALSE on failure and does not trigger warnings.

In practice, it should not be a great deal since safe mode is allegedly the only situation that can cause a failure and the feature is already deprecated.

Other than that, the function is just a wrapper for the property change.