Question

我实现了一个包含while for循环的函数，其定义如下：

func()
{
...
 for i in "$@"; do
     enum="source"
     sourceID=$i
     ret_ID $FILE_NAME $sourceID $enum
     ID=$req_ID
     ((ID+=ID))
 done
 echo $ID
}

函数ret_ID解析包含一些变量的文件

param1=0x00000001
param2=0x00000400
param3=0x000008000
...

无论我传递多少个参数，echo $ID都会返回与最后一个参数关联的ID，而不是所有参数的总和。例如，func param1 param3返回32768而非32769。

Answer 1

更新：根据OP的评论判断，glenn jackman建议切换让ret_ID() 设置全局变量为了将结果返回将其结果输出到stdout 并在命令替换中捕获结果（$(...)）解决了问题。

^{假设问题不是简单的逻辑错误，Glenn指出（((ID+=ID))应该是((ID+=req_ID ))：原始问题的确切原因不知道，但由于func()和ret_ID()都对全局变量进行操作，因此很容易看出一个函数如何干扰另一个函数，例如if ret_ID()意外地还设置了变量$ID。}

这里＆＃39;重写显示此更改的函数，并建议进行一些其他更改以使函数更加健壮，最明显的是使用本地变量：

func() { # Declare *local* variables. local arg enum sourceID retID # Declare the local result variable *as an integer* # Also, better to use variable names that at least start with a *lowercase* # letter to avoid conflicts with *environment* variables. local -i id=0 # ... for arg; do # loop over all args; the `in "$@"` part is optional enum="source" sourceID=$arg # Call helper function and let it return its result via *stdout* captured # through a command substitution rather than by setting a global variable. # Note the use of double quotes to prevent problems with values with embedded spaces. reqID=$(ret_ID "$FILE_NAME" "$sourceID" "$enum") # Add the value returned to $id # Note that since $id was declared as an integer, # use of (( ... )) is optional. id+=$reqID done echo "$id" }

在for循环中添加参数

1 个答案: