警告:格式'%s'的预期中键入'字符*',但参数2的类型'诠释' [英] warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘int’
本文介绍了警告:格式'%s'的预期中键入'字符*',但参数2的类型'诠释'的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我觉得这$ C $ c和错误是不言自明的,但我不知道为什么?
环境:
操作系统:Mac OS X 10.6.1
编译:i686的-苹果darwin10-GCC-4.2.1
code:
1的#include<&stdio.h中GT;
2#包括LT&;&stdlib.h中GT;
3#包括LT&;&netdb.h中GT;
4#包括LT&; SYS / socket.h中>
五
6 INT
7主(INT ARGC,字符** argv的)
8 {
9字符* PTR,** PPTR;
10结构hostent * hptr;
11字符海峡[32];
12
13 // PTR =的argv [1];
14 PTR =www.google.com;
15
16,如果((hptr =的gethostbyname(PTR))== NULL){
17的printf(主机的gethostbyname错误:%s \\ n,PTR);
18
19}
20的printf(官方主机名:%S \\ n,hptr-> h_name);
21
22(PPTR = hptr-> h_aliases;!* PPTR = NULL; PPTR ++)
23的printf(别名:%S \\ n,* PPTR);
24
25开关(hptr-> h_addrtype){
26的情况下AF_INET:
27的情况下AF_INET6:
28 PPTR = hptr-> h_addr_list;
29
30(* PPTR = NULL;!PPTR ++)
31的printf(地址:%S \\ n,inet_ntop(hptr-> h_addrtype,* PPTR,海峡,sizeof的(STR)));
32休息;
33默认:
34的printf(未知地址类型\\ n);
35休息;
36}
37返回0;
38}
编译器及以下执行的输出:
zhumatoMacBook:CProjects朱$ GCC gethostbynamedemo.c
gethostbynamedemo.c:在函数'主':
gethostbynamedemo.c:31:警告:格式'%s'的预期中键入'字符*',但参数2的类型'诠释'
zhumatoMacBook:CProjects朱$ ./a.out
正式的主机名:www.l.google.com
别名:www.google.com
分段故障
为什么我收到的格式警告,难道这是段错误的原因是什么?
解决方案
- 请编译使用-Wall您code。
- 包括inet_ntop头文件(ARPA / inet.h)
- 阅读inet_ntop(3)手册页和小心参数类型。
I think this code and error is self-explanatory, but I don't know why?
Environment:
OS: Mac OS X 10.6.1
Compiler: i686-apple-darwin10-gcc-4.2.1
code:
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <netdb.h>
4 #include <sys/socket.h>
5
6 int
7 main(int argc, char **argv)
8 {
9 char *ptr, **pptr;
10 struct hostent *hptr;
11 char str[32];
12
13 //ptr = argv[1];
14 ptr = "www.google.com";
15
16 if ((hptr = gethostbyname(ptr)) == NULL) {
17 printf("gethostbyname error for host:%s\n", ptr);
18
19 }
20 printf("official hostname:%s\n", hptr->h_name);
21
22 for (pptr = hptr->h_aliases; *pptr != NULL; pptr++)
23 printf(" alias:%s\n", *pptr);
24
25 switch (hptr->h_addrtype) {
26 case AF_INET:
27 case AF_INET6:
28 pptr = hptr->h_addr_list;
29
30 for (; *pptr != NULL; pptr++)
31 printf(" address:%s\n", inet_ntop(hptr->h_addrtype, *pptr, str, sizeof(str)));
32 break;
33 default:
34 printf("unknown address type\n");
35 break;
36 }
37 return 0;
38 }
compiler and executed output below:
zhumatoMacBook:CProjects zhu$ gcc gethostbynamedemo.c
gethostbynamedemo.c: In function ‘main’:
gethostbynamedemo.c:31: warning: format ‘%s’ expects type ‘char *’, but argument 2 has type ‘int’
zhumatoMacBook:CProjects zhu$ ./a.out
official hostname:www.l.google.com
alias:www.google.com
Segmentation fault
Why am I getting the format warning and could this be the cause of the segmentation fault?
解决方案
- Please compile your code using -Wall.
- include header file for inet_ntop (arpa/inet.h)
- read inet_ntop(3) man page and be careful about parameter types.
这篇关于警告:格式'%s'的预期中键入'字符*',但参数2的类型'诠释'的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文