php中变长参数在5.3以后如何实现
我想写一个变长参数的函数, 上网查询后找到func_num_args、func_get_arg和func_get_args等函数, 但在w3schol.com.cn上面没有, 所有猜测可能有兼容性问题.
于是又查到php5.3的改动之一: "•函数内 include 或者 require 一个文件时,文件内 将不能使用 func_get_arg(), func_get_args() 和 func_num_args() 函数".
那么, 问题就是php5.3版本以后要实现变长参数应该怎么写呢, 或者说如果写才最兼容, 还有就是目前使用网上买的虚拟主机上装的php都是什么版本的
回复讨论(解决方案)
printf("php %s\n", phpversion());function f() { printf("参数个数: %d 参数值: %s\n", func_num_args(), join(', ', func_get_args()));}f(1,2,3);f('a','b','c','d');
php 5.4.31参数个数: 3 参数值: 1, 2, 3参数个数: 4 参数值: a, b, c, d
php 5.6.3参数个数: 3 参数值: 1, 2, 3参数个数: 4 参数值: a, b, c, d
可见,实践是检验真理的唯一标准
出错的情况是这样子的
test.php<?phpfunction foo() { include './fga.inc';}foo('First arg', 'Second arg');?>fga.inc<?php$args = func_get_args();var_export($args);?>
这个东西
function foo() {
include './fga.inc';
}
这种写法,楼主在什么样的情境下会这么写?
要兼容,至少这样子
test.php<?phpfunction foo() { $args = func_get_args(); include './fga.inc';}foo('First arg', 'Second arg');?>fga.inc<?phpvar_export($args);?>
我还没测试,楼主你先试试
至于虚拟机,应该大多数是5.2.x和5.3.x
我试完了 第一个报错,第二个正常
printf("php %s\n", phpversion());function f() { printf("参数个数: %d 参数值: %s\n", func_num_args(), join(', ', func_get_args()));}f(1,2,3);f('a','b','c','d');
php 5.4.31参数个数: 3 参数值: 1, 2, 3参数个数: 4 参数值: a, b, c, d
php 5.6.3参数个数: 3 参数值: 1, 2, 3参数个数: 4 参数值: a, b, c, d
可见,实践是检验真理的唯一标准
您的代码中没有包含其他文件, 当然不会出错了.
另外实践也需要环境, 至少要有一个5.2以下的环境, 一个5.2以上的环境才行, 我连自己用的php是哪个版本都不知道(当然看了您的代码我现在知道了)
你的那个写法本来就是违背模块化原则的
再说 php5.2 早就因为有严重的安全问题而废止了
如果你非要去用,那也只是你个人的问题
我的是5.3.8,测试Warning: func_get_args(): Called from the global scope - no function context in E:\www\phptest\fga.inc on line 3
出错的情况是这样子的
test.php<?phpfunction foo() { include './fga.inc';}foo('First arg', 'Second arg');?>fga.inc<?php$args = func_get_args();var_export($args);?>
这个东西
function foo() {
include './fga.inc';
}
这种写法,楼主在什么样的情境下会这么写?
要兼容,至少这样子
test.php<?phpfunction foo() { $args = func_get_args(); include './fga.inc';}foo('First arg', 'Second arg');?>fga.inc<?phpvar_export($args);?>
我还没测试,楼主你先试试
至于虚拟机,应该大多数是5.2.x和5.3.x
运行 您的两个代码, 我懂 了, 我查到的那句话
"•函数内 include 或者 require 一个文件时,文件内 将不能使用 func_get_arg(), func_get_args() 和 func_num_args() 函数".
原来"文件内"指的是被包含的那个文件. 这样的代码我肯定不会写, 我只是会包含一些类或函数的文件, 不会包含全局变量.
谢谢大家, 我懂了, 是我自己理解错了那句话.

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