变量声明：unsigned int var:1 表示什么意思？

[ciml]

是否表示用一个字节存储？我判断该变量的值的时候该如何写？

[my_mtx]

无符号整数

[ripyu]

C Bit Fields
In addition to declarators for members of a structure or union, a structure declarator can also be a specified number of bits, called a “bit field.” Its length is set off from the declarator for the field name by a colon. A bit field is interpreted as an integral type. Bit fields must also be long enough to contain the bit pattern. For example, these two statements are not legal:

short a:17; /* Illegal! */
int long y:33; /* Illegal! */

[ripyu]

给分，具体可以看看MSDN

[dz_w]

这是采用位域结构存储时用的。表示用一位存储这个变量。使用时与普通结构相同，但要按定义的变量存储用的位数控制大小

[c0der]

：号后面的数字表示用多少bit来存储该变量。