WRITE和READ有什麼錯誤？

Question

這是一個關於管道和過程的小型C程序，Father過程將創建2個子進程，第一個將讀取鏈中的數字，第二個將讀取這些字母。我開始尋求WORD，我沒有添加保護，這只是一個測試，所以讓我們說約20個字母，然後父進程將編號在第一個管道，並在第二個管道中的字母，然後他將創建一個孩子使用fork（），如果他是孩子，他會從第一個管道讀取數字，如果他是父親，那麼他將創建另一個孩子，讀取這些字母。

# include <stdio.h> 
# include <unistd.h> 
# include <string.h> 
# include <fcntl.h> 

main() 
{ 
    printf("I am the father, I will create 2 sons, the first will read the numbers , the second will read the letters\n"); 
    char * word; 
    printf("please type the word: \n"); 
    scanf("%s",word); 
    printf("Now 2 pipes will be created\n"); 
    int fd1[2]; 
    int fd2[2]; 
    pipe(fd1); pipe(fd2); 
    printf("Now the father will write numbers in the first pipe, and letters in the second\n"); 
    int i; 
    char numbers[20]; int j=0; 
    char caracters[20]; int k=0; 
    for (i=0;i<20;i++) 
    { 
     if(word[i]>='0' && word[i]<='9') //if number 
     { 
      close(fd1[0]); //closing reading 
      write(fd1[1],word[i],2); 

     } 
     else 
     { 
      close(fd2[0]); 
      write(fd2[1],word[i],2); 
     } 

    } 
    printf("The father has wrote in the 2 pipes, now its time for the sons\n"); 
    int f=fork(); 
    if(f==0) //first son 
    { 
     for(i=0;i<20;i++) {   
      close(fd1[1]); //closing writing 
      read(fd1[0],numbers[j],strlen(numbers[j])+1); 
      j++; 

     } 
     printf("first son read everything, he got %d Numbers\n", j); 
    } 
    else 
    { 
     f=fork(); 
     if(f==0) 
     { 
      for(i=0;i<20;i++) {   
      close(fd2[1]); //closing writing 
      read(fd2[0],caracters[k],strlen(caracters[k])+1); 
      k++; 

     } 
     printf("second son read everything, he got %d caracters\n", j); 
    } 
} 

編譯後：

In function 'main': 
Line 25: warning: passing argument 2 of 'write' makes pointer from integer without a cast 
Line 31: warning: passing argument 2 of 'write' makes pointer from integer without a cast 
Line 41: warning: passing argument 1 of 'strlen' makes pointer from integer without a cast 
Line 41: warning: passing argument 2 of 'read' makes pointer from integer without a cast 
Line 54: warning: passing argument 1 of 'strlen' makes pointer from integer without a cast 
Line 54: warning: passing argument 2 of 'read' makes pointer from integer without a cast 
Line 60: error: expected declaration or statement at end of input 

Answer 1

的write和read的原型是

ssize_t write(int fd, const void *buf, size_t count); 

ssize_t read(int fd, void *buf, size_t count); 

參數2至write/read應該是一個指針。但是，您發送是一個字符（這實際上是一個整數）word[i]和numbers[i]

同樣的問題，即使你strlen

此外，聲明word作爲數組，而不是隻是一個指針。否則，您將寫入指針所指向的任意位置。或者如果你想保持它作爲一個指針，malloc它的一些記憶。

這一切後，剛及格的word，numbers代替numbers[j]或words[i]你的功能，這都在抱怨

編輯：另外你上次for聲明for(i=0;i<20;i++)缺少一個右括號，因此Line 60: error: expected declaration or statement at end of input錯誤

Answer 2

相反作者：

write(fd1[1],word[i],2); 

這樣做：

write(fd1[1],(void*)&word[i],2); 

......即，將POINTER傳遞到數據的位置，而不是數據本身的值。