PHP :: Bug #33516 :: Only variables can be passed by reference I am trying to add to the $params variable I tried adding a string but there was array to string error so now I am trying to push a value to the end of array Fatal error: Only variables can be passed by reference in C:\wamp\www\POPP-edition4-code\97814 30260318_C hapter_06_ Code\listi ng06.01.ph p on line 17 and what does this error mean Two or more variable/value pairs can be passed by separating them with the ampersand ( &) character. Jederzeit Heute Letzte Woche Letzter Monat. By removing the ability to include the reference sign on function calls where pass-by-reference is incurred (I.e., function definition uses &), the readability of the code suffers, as one has to look at the function definition to know if the variable being passed is by-ref or not (I.e., potential to be modified). Output 2 will be “Red”, it is an example of “ Passed by Value “. 这个问题多半是因为引用传递参数引起的，解决办法一是修改代码不使用引用传递,需要的朋友可以参考下. Pass by reference (C++ only) Pass-by-reference means to pass the reference of an argument in the calling function to the corresponding formal parameter of the called function. The result is that when you change a function to pass by reference, it will only become more efficient if, inside the function, the passed variable is having its data altered, in which case passing by reference causes your code to alter the data of the original copy. Bug #5371 :: Getting several "PHP Fatal error: Only variables can … 17 answers given for "Are PHP Variables passed by value or by reference?" If you run into this problem with nested function calls, then an easy workaround is to assign the result from array_keys (or whatever function) to an intermediary variable: PHP の`str_replace` 関数で "Fatal error: Only variables can be passed by reference in "エラー ; PHP の`str_replace` 関数で “Fatal error: Only variables can be passed by reference in “エラー.