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“无用类型限定符”错误(“useless type qualifier” error)

 以下代码出现以下错误。 我试图找出问题出在谷歌的哪个位置，但我没有找到有用的东西。  
Compiling /home/tectu/projects/resources/chibios/ext/lcd/touchpad.c
In file included from /home/tectu/projects/resources/chibios/ext/lcd/touchpad.c:1:0:
/home/tectu/projects/resources/chibios/ext/lcd/touchpad.h:17:1: warning: useless type qualifier in empty declaration [enabled by default]
 
 以下是touchpad.h第12行到第17行的代码：  
volatile struct cal {
    float xm; 
    float ym; 
    float xn; 
    float yn; 
};
 
 下面是我在touchpad.c使用这个结构的方法：  
static struct cal cal = { 
    1, 1, 0, 0  
};
 
 任何人都可以看到灯光？ ：d 

I get the following error with the following code. I tried to figure out where the problem is over Google, but I didn't find anything helpful. 
Compiling /home/tectu/projects/resources/chibios/ext/lcd/touchpad.c
In file included from /home/tectu/projects/resources/chibios/ext/lcd/touchpad.c:1:0:
/home/tectu/projects/resources/chibios/ext/lcd/touchpad.h:17:1: warning: useless type qualifier in empty declaration [enabled by default]
 
Here's the the code from line 12 to line 17 from touchpad.h: 
volatile struct cal {
    float xm; 
    float ym; 
    float xn; 
    float yn; 
};
 
And here's how I use this struct inside touchpad.c: 
static struct cal cal = { 
    1, 1, 0, 0  
};
 
Can anyone show me the light? :D

原文：https://stackoverflow.com/questions/10978370

更新时间：2023-08-25 09:08

最满意答案

 如果您使用散列而不是数组来组织EmergInfo数据，您将能够一次搜索并替换所有字段。  
my %EmergInfo = (
  Location => 'New York',
  LastUpdate => 'Feb 17, 2015',
  OPHONE1 => '800-555-1212',
  etc => '...',
);

my $joined_keys = join('|', keys %EmergInfo);
my $regexp = qr/#($joined_keys)/;

while (<DATA>) {
  s/$regexp/$EmergInfo{$1}/g;
  print;
}

__DATA__
#Location
#LastUpdate
#AddInfo
#SpecInst
#OPHONE1
 
 编辑：请注意，我在while循环外创建一次编译的正则表达式，以便它不必为循环内的每个迭代创建。 

If you organize your EmergInfo data in a hash instead of an array, you will be able to search and replace all fields at once. 
my %EmergInfo = (
  Location => 'New York',
  LastUpdate => 'Feb 17, 2015',
  OPHONE1 => '800-555-1212',
  etc => '...',
);

my $joined_keys = join('|', keys %EmergInfo);
my $regexp = qr/#($joined_keys)/;

while (<DATA>) {
  s/$regexp/$EmergInfo{$1}/g;
  print;
}

__DATA__
#Location
#LastUpdate
#AddInfo
#SpecInst
#OPHONE1
 
EDIT: note that I'm creating the compiled regular expression once outside the while loop so that it doesn't have to be created for each iteration within the loop.

“无用类型限定符”错误(“useless type qualifier” error)

最满意答案

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