PHP内核研究静态变量_PHP教程

静态变量 它可以是 静态全局变量,如果不调用unset,那么这个静态变量会一直存在,直到程序退出时才由Zend内存管理来释放 它可以是 静态局部变量:在函数里定义,函数执行完后,该静态变量不会消失 它可以是 静态成员变量:在类里定义,它可以在所有类的对象中共享 例如 "static" { return T_STATIC; } 是一个宏 再打开 zend/zend_language_pareser.l 搜 T_STATIC 找到代码 T_STATIC static_var_list ';' 跟进 static_var_list 找到代码 static_var_list: static_var_list ',' T_VARIABLE { zend_do_fetch_static_variable(&$3, NULL, ZEND_FETCH_STATIC TSRMLS_CC); } | static_var_list ',' T_VARIABLE '=' static_scalar { zend_do_fetch_static_variable(&$3, &$5, ZEND_FETCH_STATIC TSRMLS_CC); } | T_VARIABLE { zend_do_fetch_static_variable(&$1, NULL, ZEND_FETCH_STATIC TSRMLS_CC); } | T_VARIABLE '=' static_scalar { zend_do_fetch_static_variable(&$1, &$3, ZEND_FETCH_STATIC TSRMLS_CC); } ; 就是这里了..它由PHP的语法分析程序 解析成上面的代码 zend_do_fetch_static_variable 这个函数就是了 它在zend/zend_compile.c里定义 代码如下 void zend_do_fetch_static_variable(znode *varname, const znode *static_assignment, int fetch_type TSRMLS_DC) { zval *tmp; //一个临时变量 zend_op *opline; znode lval; znode result; ALLOC_ZVAL(tmp); //申请一块内存 if (static_assignment) { *tmp = static_assignment->u.constant; } else { INIT_ZVAL(*tmp); } if (!CG(active_op_array)->static_variables) {//初始化静态变量的HASH 键值 ALLOC_HASHTABLE(CG(active_op_array)->static_variables); //初始化HASH值 zend_hash_init(CG(active_op_array)->static_variables, 2, NULL, ZVAL_PTR_DTOR, 0); } zend_hash_update(CG(active_op_array)->static_variables, varname->u.constant.value.str.val, varname->u.constant.value.str.len+1, &tmp, sizeof(zval *), NULL); if (varname->op_type == IS_CONST) { if (Z_TYPE(varname->u.constant) != IS_STRING) { convert_to_string(&varname->u.constant); } } opline = get_next_op(CG(active_op_array) TSRMLS_CC); opline->result.op_type = IS_VAR; opline->result.u.EA.type = 0; opline->result.u.var = get_temporary_variable(CG(active_op_array)); opline->op1 = *varname; SET_UNUSED(opline->op2); opline->op2.u.EA.type = ZEND_FETCH_STATIC; result = opline->result; if (varname->op_type == IS_CONST) { zval_copy_ctor(&varname->u.constant); } fetch_simple_variable(&lval, varname, 0 TSRMLS_CC); /* Relies on the fact that the default fetch is BP_VAR_W */ www.2cto.com if (fetch_type == ZEND_FETCH_LEXICAL) { znode dummy; zend_do_begin_variable_parse(TSRMLS_C); zend_do_assign(&dummy, &lval, &result TSRMLS_CC); zend_do_free(&dummy TSRMLS_CC); } else { zend_do_assign_ref(NULL, &lval, &result TSRMLS_CC); } CG(active_op_array)->opcodes[CG(active_op_array)->last-1].result.u.EA.type |= EXT_TYPE_UNUSED; /* zval_dtor(&varname->u.constant); */ }

http://www.bkjia.com/PHPjc/477784.htmlwww.bkjia.comtruehttp://www.bkjia.com/PHPjc/477784.htmlTechArticle静态变量 它可以是 静态全局变量,如果不调用unset,那么这个静态变量会一直存在,直到程序退出时才由Zend内存管理来释放 它可以是 静态局部...