const static unsigned char **ip;
const static unsigned long int **port;
const static unsigned char **cmd;
const static const long unsigned int **newsockfd;
const static const long unsigned int **n;
const static long unsigned int *listenfd;
const static long unsigned int *clien;
if (newsockfd < 0)
error("ERROR on accept");
bzero(cmd,256);
n = read(newsockfd,cmd,255);
if (n < 0) error("ERROR reading from socket");
printf("Here is the message: %s\n",cmd);
n = write(newsockfd,"I got your message",18);
if (n < 0) error("ERROR writing to socket");
close(newsockfd);
}
close(sockfd);
return 0;
}
Seu programa nem compila. Recomendo tratar as mensagens de erro mostradas.
$ gcc -Wall -Werror -O2 -pedantic-errors -c x.c
x.c: In function ‘main’:
x.c:56:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
listenfd = socket(AF_INET, SOCK_STREAM, 0);
^
x.c:57:8: error: passing argument 1 of ‘bind’ makes integer from pointer without a cast [-Wint-conversion]
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)
^
In file included from /usr/include/arpa/inet.h:22:0,
from x.c:6:
x.c:63:37: error: passing argument 1 of ‘__bswap_32’ makes integer from pointer without a cast [-Wint-conversion]
serv_addr.sin_addr.s_addr = htonl(ip);
^
In file included from /usr/include/endian.h:60:0,
from /usr/include/x86_64-linux-gnu/bits/waitstatus.h:64,
from /usr/include/stdlib.h:42,
from x.c:2:
/usr/include/x86_64-linux-gnu/bits/byteswap.h:45:1: note: expected ‘unsigned int’ but argument is of type ‘const unsigned char **’
__bswap_32 (unsigned int __bsx)
^
x.c:66:16: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (listenfd <= 0)
^
x.c:69:18: error: passing argument 1 of ‘setsockopt’ makes integer from pointer without a cast [-Wint-conversion]
if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int))
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:226:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int setsockopt (int __fd, int __level, int __optname,
^
x.c:72:8: error: passing argument 1 of ‘bind’ makes integer from pointer without a cast [-Wint-conversion]
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)
^
x.c:74:10: error: passing argument 1 of ‘listen’ makes integer from pointer without a cast [-Wint-conversion]
listen(listenfd, 10);
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int listen (int __fd, int __n) __THROW;
^
x.c:77:13: error: passing argument 1 of ‘listen’ makes integer from pointer without a cast [-Wint-conversion]
listen(listenfd, 10);
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int listen (int __fd, int __n) __THROW;
^
x.c:78:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
clien = sizeof(serv_addr);
^
x.c:84:29: error: ‘sockfd’ undeclared (first use in this function)
newsockfd = accept(sockfd,
^
x.c:84:29: note: each undeclared identifier is reported only once for each function it appears in
x.c:86:18: error: passing argument 3 of ‘accept’ from incompatible pointer type [-Wincompatible-pointer-types]
&clien);
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:243:12: note: expected ‘socklen_t * restrict {aka unsigned int * restrict}’ but argument is of type ‘const long unsigned int **’
extern int accept (int __fd, __SOCKADDR_ARG __addr,
^
x.c:88:24: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (newsockfd < 0)
^
x.c:89:14: error: implicit declaration of function ‘error’ [-Wimplicit-function-declaration]
error("ERROR on accept");
^
x.c:91:14: error: implicit declaration of function ‘read’ [-Wimplicit-function-declaration]
n = read(newsockfd,cmd,255);
^
x.c:91:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
n = read(newsockfd,cmd,255);
^
x.c:92:16: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (n < 0) error("ERROR reading from socket");
^
x.c:93:17: error: format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘const unsigned char **’ [-Werror=format=]
printf("Here is the message: %s\n",cmd);
^
x.c:94:14: error: implicit declaration of function ‘write’ [-Wimplicit-function-declaration]
n = write(newsockfd,"I got your message",18);
^
x.c:94:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
n = write(newsockfd,"I got your message",18);
^
x.c:95:16: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (n < 0) error("ERROR writing to socket");
^
x.c:96:10: error: implicit declaration of function ‘close’ [-Wimplicit-function-declaration]
close(newsockfd);
^
cc1: all warnings being treated as errors
Boa parte dos erros tem a ver com tipos errôneos das variáveis. Entre outros, você usou ponteiros onde não deveria tê-los usado. Alguma razão para isso?
if (setsockopt(x, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int)) < 0)
perror("setsockopt(SO_REUSEADDR) failed");
}
/* execute the program */
int main(int argc, char *argv[])
{
shell();
}
4. Re: Cliente socket escrito em C [AJUDA!]
mrx6s0usa Ubuntu
Post recolhido
Enviado em 06/10/2017 - 23:40h
paulo1205 escreveu:
Seu programa nem compila. Recomendo tratar as mensagens de erro mostradas.
$ gcc -Wall -Werror -O2 -pedantic-errors -c x.c
x.c: In function ‘main’:
x.c:56:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
listenfd = socket(AF_INET, SOCK_STREAM, 0);
^
x.c:57:8: error: passing argument 1 of ‘bind’ makes integer from pointer without a cast [-Wint-conversion]
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)
^
In file included from /usr/include/arpa/inet.h:22:0,
from x.c:6:
x.c:63:37: error: passing argument 1 of ‘__bswap_32’ makes integer from pointer without a cast [-Wint-conversion]
serv_addr.sin_addr.s_addr = htonl(ip);
^
In file included from /usr/include/endian.h:60:0,
from /usr/include/x86_64-linux-gnu/bits/waitstatus.h:64,
from /usr/include/stdlib.h:42,
from x.c:2:
/usr/include/x86_64-linux-gnu/bits/byteswap.h:45:1: note: expected ‘unsigned int’ but argument is of type ‘const unsigned char **’
__bswap_32 (unsigned int __bsx)
^
x.c:66:16: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (listenfd <= 0)
^
x.c:69:18: error: passing argument 1 of ‘setsockopt’ makes integer from pointer without a cast [-Wint-conversion]
if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int))
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:226:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int setsockopt (int __fd, int __level, int __optname,
^
x.c:72:8: error: passing argument 1 of ‘bind’ makes integer from pointer without a cast [-Wint-conversion]
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)
^
x.c:74:10: error: passing argument 1 of ‘listen’ makes integer from pointer without a cast [-Wint-conversion]
listen(listenfd, 10);
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int listen (int __fd, int __n) __THROW;
^
x.c:77:13: error: passing argument 1 of ‘listen’ makes integer from pointer without a cast [-Wint-conversion]
listen(listenfd, 10);
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ‘int’ but argument is of type ‘const long unsigned int *’
extern int listen (int __fd, int __n) __THROW;
^
x.c:78:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
clien = sizeof(serv_addr);
^
x.c:84:29: error: ‘sockfd’ undeclared (first use in this function)
newsockfd = accept(sockfd,
^
x.c:84:29: note: each undeclared identifier is reported only once for each function it appears in
x.c:86:18: error: passing argument 3 of ‘accept’ from incompatible pointer type [-Wincompatible-pointer-types]
&clien);
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:243:12: note: expected ‘socklen_t * restrict {aka unsigned int * restrict}’ but argument is of type ‘const long unsigned int **’
extern int accept (int __fd, __SOCKADDR_ARG __addr,
^
x.c:88:24: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (newsockfd < 0)
^
x.c:89:14: error: implicit declaration of function ‘error’ [-Wimplicit-function-declaration]
error("ERROR on accept");
^
x.c:91:14: error: implicit declaration of function ‘read’ [-Wimplicit-function-declaration]
n = read(newsockfd,cmd,255);
^
x.c:91:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
n = read(newsockfd,cmd,255);
^
x.c:92:16: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (n < 0) error("ERROR reading from socket");
^
x.c:93:17: error: format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘const unsigned char **’ [-Werror=format=]
printf("Here is the message: %s\n",cmd);
^
x.c:94:14: error: implicit declaration of function ‘write’ [-Wimplicit-function-declaration]
n = write(newsockfd,"I got your message",18);
^
x.c:94:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
n = write(newsockfd,"I got your message",18);
^
x.c:95:16: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (n < 0) error("ERROR writing to socket");
^
x.c:96:10: error: implicit declaration of function ‘close’ [-Wimplicit-function-declaration]
close(newsockfd);
^
cc1: all warnings being treated as errors
Boa parte dos erros tem a ver com tipos errôneos das variáveis. Entre outros, você usou ponteiros onde não deveria tê-los usado. Alguma razão para isso?
paulo1205 escreveu:
Seu programa nem compila. Recomendo tratar as mensagens de erro mostradas.
$ gcc -Wall -Werror -O2 -pedantic-errors -c x.c
x.c: In function ?main?:
x.c:56:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
listenfd = socket(AF_INET, SOCK_STREAM, 0);
^
x.c:57:8: error: passing argument 1 of ?bind? makes integer from pointer without a cast [-Wint-conversion]
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ?int? but argument is of type ?const long unsigned int *?
extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)
^
In file included from /usr/include/arpa/inet.h:22:0,
from x.c:6:
x.c:63:37: error: passing argument 1 of ?__bswap_32? makes integer from pointer without a cast [-Wint-conversion]
serv_addr.sin_addr.s_addr = htonl(ip);
^
In file included from /usr/include/endian.h:60:0,
from /usr/include/x86_64-linux-gnu/bits/waitstatus.h:64,
from /usr/include/stdlib.h:42,
from x.c:2:
/usr/include/x86_64-linux-gnu/bits/byteswap.h:45:1: note: expected ?unsigned int? but argument is of type ?const unsigned char **?
__bswap_32 (unsigned int __bsx)
^
x.c:66:16: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (listenfd <= 0)
^
x.c:69:18: error: passing argument 1 of ?setsockopt? makes integer from pointer without a cast [-Wint-conversion]
if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof(int))
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:226:12: note: expected ?int? but argument is of type ?const long unsigned int *?
extern int setsockopt (int __fd, int __level, int __optname,
^
x.c:72:8: error: passing argument 1 of ?bind? makes integer from pointer without a cast [-Wint-conversion]
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:123:12: note: expected ?int? but argument is of type ?const long unsigned int *?
extern int bind (int __fd, __CONST_SOCKADDR_ARG __addr, socklen_t __len)
^
x.c:74:10: error: passing argument 1 of ?listen? makes integer from pointer without a cast [-Wint-conversion]
listen(listenfd, 10);
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ?int? but argument is of type ?const long unsigned int *?
extern int listen (int __fd, int __n) __THROW;
^
x.c:77:13: error: passing argument 1 of ?listen? makes integer from pointer without a cast [-Wint-conversion]
listen(listenfd, 10);
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:233:12: note: expected ?int? but argument is of type ?const long unsigned int *?
extern int listen (int __fd, int __n) __THROW;
^
x.c:78:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
clien = sizeof(serv_addr);
^
x.c:84:29: error: ?sockfd? undeclared (first use in this function)
newsockfd = accept(sockfd,
^
x.c:84:29: note: each undeclared identifier is reported only once for each function it appears in
x.c:86:18: error: passing argument 3 of ?accept? from incompatible pointer type [-Wincompatible-pointer-types]
&clien);
^
In file included from /usr/include/netinet/in.h:23:0,
from /usr/include/arpa/inet.h:22,
from x.c:6:
/usr/include/x86_64-linux-gnu/sys/socket.h:243:12: note: expected ?socklen_t * restrict {aka unsigned int * restrict}? but argument is of type ?const long unsigned int **?
extern int accept (int __fd, __SOCKADDR_ARG __addr,
^
x.c:88:24: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (newsockfd < 0)
^
x.c:89:14: error: implicit declaration of function ?error? [-Wimplicit-function-declaration]
error("ERROR on accept");
^
x.c:91:14: error: implicit declaration of function ?read? [-Wimplicit-function-declaration]
n = read(newsockfd,cmd,255);
^
x.c:91:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
n = read(newsockfd,cmd,255);
^
x.c:92:16: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (n < 0) error("ERROR reading from socket");
^
x.c:93:17: error: format ?%s? expects argument of type ?char *?, but argument 2 has type ?const unsigned char **? [-Werror=format=]
printf("Here is the message: %s\n",cmd);
^
x.c:94:14: error: implicit declaration of function ?write? [-Wimplicit-function-declaration]
n = write(newsockfd,"I got your message",18);
^
x.c:94:12: error: assignment makes pointer from integer without a cast [-Wint-conversion]
n = write(newsockfd,"I got your message",18);
^
x.c:95:16: error: ordered comparison of pointer with integer zero [-Wpedantic]
if (n < 0) error("ERROR writing to socket");
^
x.c:96:10: error: implicit declaration of function ?close? [-Wimplicit-function-declaration]
close(newsockfd);
^
cc1: all warnings being treated as errors
Boa parte dos erros tem a ver com tipos errôneos das variáveis. Entre outros, você usou ponteiros onde não deveria tê-los usado. Alguma razão para isso?
Bom, eu não encontrei muita coisa sobre ponteiros envolvendo sockets, fiquei meio perdido...
Mas estou encontrando os erros.
Eu acabei de arrumar, é bem trivial, mas funcional. Vou melhorando aos poucos.
Toda ajuda é bem vinda para tratar melhor a escrita do código.
5. Re: Cliente socket escrito em C [AJUDA!] [RESOLVIDO]
mrx6s0usa Ubuntu
Post recolhido
Enviado em 06/10/2017 - 23:52h
No caso, fiquei em dúvida quanto á declaração das variáveis contidas na struct
typedef struct client {
char * ip;
int port;
const static unsigned char **ip;
const static int *port;
ou por estarem contidas na struct, toda vez que me referenciar à elas, serão invocadas?
Abraço.
6. Re: Cliente socket escrito em C [AJUDA!]
paulo1205usa Ubuntu
Post recolhido
Enviado em 07/10/2017 - 00:14h
Caro mrx6s0,
Eu recomendo que você sempre compile o programa com opções de diagnóstico ligadas, pois elas ajudam a identificar, entre outras coisas, erros com relação a tipos de variáveis, variáveis utilizadas sem um valor inicial conhecido, variáveis que nunca são utilizadas, comandos que nunca serão executados, e outros.
Se você estiver usando GCC ou Clang, as opções de compilação que eu recomendo são: -Wall -Werror -pedantic-errors -O2.
Campos de uma estrutura não têm relação com variáveis declaradas fora da estrutura, mesmo que elas tenham o mesmo nome desses campos.
Uma estrutura não é uma variável. Uma estrutura é uma definição de um tipo de dado composto por elementos de dados menores (os campos da estrutura), a fim de declarar variáveis que sejam desse tipo composto. Se, por exemplo, você declara uma estrutura X contendo os campos a e b, e as variáveis x e y com o tipo struct X, então a variável x será enxergada como um objeto diferente de y, de modo que x.a pode ter um valor diferente de y.a, que será também diferente de uma variável isolada a, e x.b pode ter um valor independente de y.b e independente da variável isolada b.
Você está estudando C por meio de alguma apostila, livro ou curso, ou está apenas tentando aprender com base em exemplos? Parece-me que você precisa de um pouco de teoria, que fica difícil de transmitir por um fórum como este.
7. Re: Cliente socket escrito em C [AJUDA!]
mrx6s0usa Ubuntu
Post recolhido
Enviado em 07/10/2017 - 01:51h
paulo1205 escreveu:
Caro mrx6s0,
Eu recomendo que você sempre compile o programa com opções de diagnóstico ligadas, pois elas ajudam a identificar, entre outras coisas, erros com relação a tipos de variáveis, variáveis utilizadas sem um valor inicial conhecido, variáveis que nunca são utilizadas, comandos que nunca serão executados, e outros.
Se você estiver usando GCC ou Clang, as opções de compilação que eu recomendo são: -Wall -Werror -pedantic-errors -O2.
Campos de uma estrutura não têm relação com variáveis declaradas fora da estrutura, mesmo que elas tenham o mesmo nome desses campos.
Uma estrutura não é uma variável. Uma estrutura é uma definição de um tipo de dado composto por elementos de dados menores (os campos da estrutura), a fim de declarar variáveis que sejam desse tipo composto. Se, por exemplo, você declara uma estrutura X contendo os campos a e b, e as variáveis x e y com o tipo struct X, então a variável x será enxergada como um objeto diferente de y, de modo que x.a pode ter um valor diferente de y.a, que será também diferente de uma variável isolada a, e x.b pode ter um valor independente de y.b e independente da variável isolada b.
Você está estudando C por meio de alguma apostila, livro ou curso, ou está apenas tentando aprender com base em exemplos? Parece-me que você precisa de um pouco de teoria, que fica difícil de transmitir por um fórum como este.
Pois então, eu estudo por conta, com uns livros e apostilas que tenho. Mas no caso, não faço faculdade voltada a computação, logo,meu tempo se limita bastante para o estudo da programação, computação em geral. Estou sempre estudando o que posso.
Vou me guiando pelos meus acertos e erros, digamos.
Estou usando usando as struct pois li sobre otimização de códigos, e usá-las é um bom método. Método tal que não sei se estou aplicando corretamente.
Esse código tem outras funções... mas algo que eu preciso é manter a rotina de conexão após o servidor ''desligar". Adcionar exceções de erro seria uma "saída"?
Aliás, existem métodos adequados para tal?
Atenciosamente,
8. Protótipo funcional. [adaptado]
mrx6s0usa Ubuntu
Post recolhido
Enviado em 08/10/2017 - 04:14h
Senhores, segue um protótipo funcional de uma conexão socket, no lado cliente.
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