[英]dereferencing pointer to incomplete type tcphdr->members
我使用套接字捕獲tcp數據,但構建失敗。 我的環境是Visual Studio2017。輸出錯誤:
1>/root/projects/frame_capture/framecapture.c:199:60:error : dereferencing pointer to incomplete type
1> int header_size = sizeof(struct ethhdr) + iphdrlen + (tcph->doff) * 4;
另外,Visual Studio 2017命令行是:
"gcc" -W"switch" -W"no-deprecated-declarations" -W"empty-body" -W"conversion" -W"return-type" -W"parentheses" -W"no-pointer-sign" -W"no-format" -W"uninitialized" -W"unreachable-code" -W"unused-function" -W"unused-value" -W"unused-variable" -std=c++14 -x c -Wall -fno-strict-aliasing -g2 -gdwarf-2 "g++" -O0 "3600000" -fthreadsafe-statics -W"switch" -W"no-deprecated-declarations" -W"empty-body" -W"conversion" -W"return-type" -W"parentheses" -W"no-format" -W"uninitialized" -W"unreachable-code" -W"unused-function" -W"unused-value" -W"unused-variable" -frtti -fno-omit-frame-pointer -std=c11 -fexceptions -o "D:\linuxCproject\frame_capture\frame_capture\obj\x64\Debug\%(filename).o"
我在Linux中用gcc構建它,一切成功。 linux代碼:
[root@localhost netinet]# gcc -o o.out framecapture.c
我想知道如何在Visual Studio中解決此問題。 代碼行:
unsigned short iphdrlen;
struct iphdr *iph = (struct iphdr *)(Buffer + sizeof(struct ethhdr));
iphdrlen = iph->ihl * 4;
struct tcphdr *tcph = (struct tcphdr*)(Buffer + iphdrlen + sizeof(struct ethhdr));
int header_size = sizeof(struct ethhdr) + iphdrlen + (tcph->doff) * 4;
但是我包括.h文件,如下所示:
#include<netinet/tcp.h> //Provides declarations for tcp header
tcp.h中的定義是這樣的:
# else /* !__FAVOR_BSD */
struct tcphdr
{
u_int16_t source;
u_int16_t dest;
u_int32_t seq;
u_int32_t ack_seq;
# if __BYTE_ORDER == __LITTLE_ENDIAN
u_int16_t res1:4;
u_int16_t doff:4;
u_int16_t fin:1;
u_int16_t syn:1;
u_int16_t rst:1;
u_int16_t psh:1;
u_int16_t ack:1;
u_int16_t urg:1;
u_int16_t res2:2;
# elif __BYTE_ORDER == __BIG_ENDIAN
u_int16_t doff:4;
u_int16_t res1:4;
u_int16_t res2:2;
u_int16_t urg:1;
u_int16_t ack:1;
u_int16_t psh:1;
u_int16_t rst:1;
u_int16_t syn:1;
u_int16_t fin:1;
# else
# error "Adjust your <bits/endian.h> defines"
# endif
u_int16_t window;
u_int16_t check;
u_int16_t urg_ptr;
};
# endif /* __FAVOR_BSD */
最后,我通過探索解決了這個問題。
主要問題是構建命令。
工程->專家-> C / C ++->語言-> C語言標准選擇正確的標准,如C99 / C89或其他,我選擇了Default來解決編譯問題。 將c ++語言標准設置為與C相同,我也選擇默認設置。
之后,我得到命令行:
"gcc" -W"switch" -W"no-deprecated-declarations" -W"empty-body" -W"conversion" -W"return-type" -W"parentheses" -W"no-pointer-sign" -W"no-format" -W"uninitialized" -W"unreachable-code" -W"unused-function" -W"unused-value" -W"unused-variable" -Wall -fno-strict-aliasing -g2 -gdwarf-2 "g++" -O0 "3600000" -fthreadsafe-statics -W"switch" -W"no-deprecated-declarations" -W"empty-body" -W"conversion" -W"return-type" -W"parentheses" -W"no-format" -W"uninitialized" -W"unreachable-code" -W"unused-function" -W"unused-value" -W"unused-variable" -frtti -fno-omit-frame-pointer -fexceptions -o "D:\linuxCproject\icmprequest\icmprequest\obj\x64\Debug\%(filename).o"
提示:處理!__FAVOR_BSD
時,不同的標准會有所不同。
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