问题1: 编译选项报错, 未识别 -Wshift-negative-value
选项
Building project file: main/src/main.c
Building project file: main/src/mouse_cursor_icon.c
cc: error: unrecognized command line option ‘-Wshift-negative-value’
cc: error: unrecognized command line option ‘-Wshift-negative-value’
Makefile:57: recipe for target 'build/obj/main/src/main.o' failed
make: *** [build/obj/main/src/main.o] Error 1
make: *** Waiting for unfinished jobs....
Makefile:57: recipe for target 'build/obj/main/src/mouse_cursor_icon.o' failed
make: *** [build/obj/main/src/mouse_cursor_icon.o] Error 1
原因: -Wshift-negative-value
选项的作用是检查左移操作(<<)中可能出现的负数。
当一个负数被左移时,结果通常是未定义的。在某些硬件和编译器实现中,这样的操作可能产生一个未定义的结果或者异常。为了防止这种情况,GCC 提供了一个警告来帮助开发者检测这样的潜在问题。
比如:
int x = -5;
x <<= 2; // This operation is not defined for negative numbers
所以, 编译的时