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Ctype

C 语言中不同的 char

  1. char, signed char, unsigned char 是三种不同的类型

例子：

  char a=-1;
  signed char b = -1;
  unsigned char c = -1;
  printf("%d %d %d",a,b,c)
  x86: -1 -1 255
  arm: 255 -1 255
  ppc: 255 -1 255

gcc 编译选项有：

  -funsigned-char 
  -fno-signed-char 
  -fsigned-char 
  -fno-unsigned-char

　　这四个参数是对char类型进行设置,决定将char类型设置成unsigned char(前两个参数)或者 signed char(后两个参数)