我必须创建一个客户端和服务器，客户端将发送一个字符和一个整数（使用结构），然后我的客户端将迭代字母n（整数）次，并将其发送回客户端。 / p>
例如：a和4从客户端发送，服务器将操作并将4 a（aaaa）的字符串发送回客户端。
我知道我非常接近获取代码但是一旦我发送了我的char和int，我得到了一个＆＃34;分段错误（核心转储）错误＆＃34;。我完成了我的研究，错误显示是由于缺少强制转换，访问的内存不应该访问，或者指针可能为空。
代码如下：
客户端：
// ClientTest.c
// opens fifo1 for writing and fifo2 for reading
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
struct problem {
char letter[1];
int number[1];
};
main (void)
{
struct problem x=0; //Initializing structure to null
int fda; // to write to character server
int fdb; // to read response from character server
int i; // for the iteration
printf("Client: Please enter a character: ");
scanf("%c", &x.letter[0]);
printf("Client: Please enter an integer: ");
scanf("%d", &x.number[0]);
memset(&x.letter, 0, 1);
memset(&x.number, 0, 1);
if((fda=open("FIFO1", O_WRONLY))<0)//opening and validating fifos
printf("cant open fifo to write");
if((fdb=open("FIFO2", O_RDONLY))<0)
printf("cant open fifo to read");
write(fda, x.number, 1);
printf("\nClient: Got the integer sent, now waiting for response ");
//sleep(0.250);
write(fda, x.letter, 1);
printf("\nClient: Got the character sent, now waiting for response ");
char outletter[7];
read(fdb, outletter, 7);
printf("\nClient: received characters from server %c", outletter);
close(fda);
close(fdb);
printf ("\nall done!\n");
}
服务器
// ServerTest.c
// makes 2 fifos named fifo1 and fifo2
// opens fifo1 for reading and fifo2 for writing
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
struct problem {
char letter[1]; // struct to store the character
int number [1]; // struct to store the integer
};
main (void)
{
struct problem x;
int fda; // to read from client char
int fdb; // to write to client char
int finish; // lets me know that client is done
int i; // because C needs this defined as int
int p;
char outletter[7];
memset(&x.letter, 0, 7);
memset(&x.number, 0, 1);
/* Create the fifos and open them */
if ((mkfifo("FIFO1",0666)<0 && errno != EEXIST))
{
perror("cant create FIFO1");
exit(-1);
}
if ((mkfifo("FIFO2",0666)<0 && errno != EEXIST))
{
perror("cant create FIFO2");
exit(-1);
}
if((fda=open("FIFO1", O_RDONLY))<0)
printf("cant open fifo to write");
if((fdb=open("FIFO2", O_WRONLY))<0)
printf("cant open fifo to read");
read(fda, x.letter, 1); //read the character
read(fda, x.number, 1); //read the integer
printf("\nServer: just got character: , %c", x.letter[0]);
printf("\nServer: just got integer: , %d", x.number[0]);
p=x.number[0]-'0';
for( i = 0; i<=p; i++) // iteration to create the character's string
outletter[p] = x.letter[0];
printf("iteration: %d and character: %c\n", i, outletter[0]); // validating the character and integer received
printf("\nServer: outchar is, %s", outletter); // this shows the character to be sent back to client
write(fdb, outletter, p);
printf("\nServer: Got the characters sent: %s", outletter ); // this sends the letter back to client
if(finish == 1)
printf("\nServer: This says I am ready to close ");
close(fda);
close(fdb);
unlink("FIFO1");
unlink("FIFO2");
}
答案 0 :(得分：1)
您的代码存在许多问题，我已经让它运行但您仍然可以改进它。
客户端：
// ClientTest.c
// opens fifo1 for writing and fifo2 for reading
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
struct problem {
char letter[1];
int number[1];
};
main (void)
{
struct problem x;
int fda; // to write to character server
int fdb; // to read response from character server
int i; // for the iteration
memset(&x, 0, sizeof(struct problem)) ;
printf("Client: Please enter a character: ");
scanf("%c", x.letter);
printf("Client: Please enter an integer: ");
scanf("%d", x.number);
// removed or else the letter and number would be reverted to zero
// memset(&x.letter, 0, sizeof(char));
// memset(&x.number, 0, sizeof(int));
if((fda=open("FIFO1", O_WRONLY))<0)//opening and validating fifos
printf("cant open fifo to write");
if((fdb=open("FIFO2", O_RDONLY))<0)
printf("cant open fifo to read");
write(fda, x.letter, sizeof(char));
printf("\nClient: Got the character sent, now waiting for response ");
write(fda, x.number, sizeof(int));
printf("\nClient: Got the integer sent, now waiting for response ");
//sleep(0.250);
char outletter[7];
read(fdb, outletter, 7);
printf("\nClient: received characters from server:") ;
printf("%s\n", outletter);
close(fda);
close(fdb);
printf ("\nall done!\n");
}
服务器：
// ServerTest.c
// makes 2 fifos named fifo1 and fifo2
// opens fifo1 for reading and fifo2 for writing
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
struct problem {
char letter[1]; // struct to store the character
int number[1]; // struct to store the integer
};
main (void)
{
struct problem x;
int fda; // to read from client char
int fdb; // to write to client char
int finish; // lets me know that client is done
int i; // because C needs this defined as int
int p;
char outletter[7];
memset(x.letter, 0, sizeof(char));
memset(x.number, 0, sizeof(int));
/* Create the fifos and open them */
if ((mkfifo("FIFO1",0666)<0 && errno != EEXIST))
{
perror("cant create FIFO1");
exit(-1);
}
if ((mkfifo("FIFO2",0666)<0 && errno != EEXIST))
{
perror("cant create FIFO2");
exit(-1);
}
if((fda=open("FIFO1", O_RDONLY))<0)
printf("cant open fifo to write");
if((fdb=open("FIFO2", O_WRONLY))<0)
printf("cant open fifo to read");
read(fda, x.letter, sizeof(char)); //read the character
read(fda, x.number, sizeof(int)); //read the integer
printf("\nServer: just got character: , %c", x.letter[0]);
printf("\nServer: just got integer: , %d", x.number[0]);
p=x.number[0];
if (p > 6) p = 6; // Cannot write more than 6 characters in outletter
for( i = 0; i<=p; i++) { // iteration to create the character's string
outletter[i] = x.letter[0];
printf("iteration: %d and character: %c\n", i, outletter[i]); // validating the character and integer received
}
outletter[p] = '\0'; // the string must finish with '\0'
printf("\nServer: outchar is, %s", outletter); // this shows the character to be sent back to client
write(fdb, outletter, p);
printf("\nServer: Got the characters sent: %s", outletter ); // this sends the letter back to client
if(finish == 1)
printf("\nServer: This says I am ready to close ");
close(fda);
close(fdb);
unlink("FIFO1");
unlink("FIFO2");
}