编译内核错误：Can't use 'defined(@array)' (Maybe you should just omit the defined()?) at kernel/timeconst.pl line 373

最近在编译一个新的rk sdk的时候，编译内核报错

  CHK     include/linux/version.h
  CHK     include/generated/utsrelease.h
make[1]: 'include/generated/mach-types.h' is up to date.
  CALL    scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  TIMEC   kernel/timeconst.h
Can't use 'defined(@array)' (Maybe you should just omit the defined()?) at kernel/timeconst.pl line 373.
/home/liuxueneng/workCode/rk3066/kernel/kernel/Makefile:141: recipe for target 'kernel/timeconst.h' failed
make[1]: *** [kernel/timeconst.h] Error 255
Makefile:973: recipe for target 'kernel' failed
make: *** [kernel] Error 2

显示错误

Can't use 'defined(@array)' (Maybe you should just omit the defined()?) at kernel/timeconst.pl line 373

已经提示纤细的错误信息在哪里了，打开timeconst.ps看一下

 372        @val = @{$canned_values{$hz}};                                        
 373         if (!defined(@val)) {                                                          
 374                 @val = compute_values($hz);                                   
 375         }                                                                     
 376         output($hz, @val);

改成如下就可以编译了

 372        @val = @{$canned_values{$hz}};                                        
 373         if (!@val) {                                                          
 374                 @val = compute_values($hz);                                   
 375         }                                                                     
 376         output($hz, @val);

参考http://blog.5ibc.net/p/48570.html

查了一下更新，发现其中有一项是perl版本升级到了 v5.22.1，然后查了perl官方文档，发现官网因为一个bug，该版本将defined(@array)去掉了。可以直接使用数组判断非空。