C: 警告：unknown conversion type character ‘ ’ in format； sizeof,size_t

sizeof.c:10:27: warning: unknown conversion type character ‘x0a’ in format [-Wformat=]
printf(“sizeof(double)=%zn”, sizeof(double));
^~
这里是说，%z的后面还需要跟一个类型转换符，比如u/d 之类的；
但是z后面跟了一个换行符；

编译器也是的，既然%z就标识着是size_t的类型，这个类型的数据类型也就固定了，还要别的转换符干啥用。
而且这个size_t的检测，静态代码检查工具和编译器的检查方式还不一样。

https://www.gnu.org/software/libc/manual/html_node/Integer-Conversions.html

#include <stdio.h>

int main()
{
        int a[3];
        printf("sizeof(double)=%dn", sizeof(double));
        printf("sizeof(double)=%ldn", sizeof(double));
        printf("sizeof(double)=%un", sizeof(double));
        printf("sizeof(double)=%lun", sizeof(double));
        printf("sizeof(double)=%zn", sizeof(double));
        printf("sizeof(double)=%Zn", sizeof(double));
        printf("sizeof(double)=%zun", sizeof(double));
        printf("sizeof(double)=%zlun", sizeof(double));
        printf("sizeof(double)=%Zun", sizeof(double));
        printf("sizeof(double)=%mn", sizeof(double));
        return 1;
}

[root@10 test]# gcc -Wall sizeof.c
sizeof.c: In function ‘main’:
sizeof.c:6:26: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘long unsigned int’ [-Wformat=]
  printf("sizeof(double)=%dn", sizeof(double));
                         ~^     ~~~~~~~~~~~~~~
                         %ld
sizeof.c:8:26: warning: format ‘%u’ expects argument of type ‘unsigned int’, but argument 2 has type ‘long unsigned int’ [-Wformat=]
  printf("sizeof(double)=%un", sizeof(double));
                         ~^     ~~~~~~~~~~~~~~
                         %lu
sizeof.c:10:27: warning: unknown conversion type character ‘x0a’ in format [-Wformat=]
  printf("sizeof(double)=%zn", sizeof(double));
                           ^~
sizeof.c:10:9: warning: too many arguments for format [-Wformat-extra-args]
  printf("sizeof(double)=%zn", sizeof(double));
         ^~~~~~~~~~~~~~~~~~~~~
sizeof.c:11:27: warning: unknown conversion type character ‘x0a’ in format [-Wformat=]
  printf("sizeof(double)=%Zn", sizeof(double));
                           ^~
sizeof.c:11:9: warning: too many arguments for format [-Wformat-extra-args]
  printf("sizeof(double)=%Zn", sizeof(double));
         ^~~~~~~~~~~~~~~~~~~~~
sizeof.c:13:27: warning: unknown conversion type character ‘l’ in format [-Wformat=]
  printf("sizeof(double)=%zlun", sizeof(double));
                           ^
sizeof.c:13:9: warning: too many arguments for format [-Wformat-extra-args]
  printf("sizeof(double)=%zlun", sizeof(double));
         ^~~~~~~~~~~~~~~~~~~~~~~
sizeof.c:15:9: warning: too many arguments for format [-Wformat-extra-args]
  printf("sizeof(double)=%mn", sizeof(double));
         ^~~~~~~~~~~~~~~~~~~~~
sizeof.c:5:6: warning: unused variable ‘a’ [-Wunused-variable]
  int a[3];
      ^

最后

以上就是贤惠书包为你收集整理的C: 警告：unknown conversion type character ‘ ’ in format； sizeof,size_t的全部内容，希望文章能够帮你解决C: 警告：unknown conversion type character ‘ ’ in format； sizeof,size_t所遇到的程序开发问题。

如果觉得靠谱客网站的内容还不错，欢迎将靠谱客网站推荐给程序员好友。