c - C中奇怪的malloc错误，将单词分词

我试图用空格和引号来标记一个单词，但是在正确的输出之后，出现了一个奇怪的malloc错误。
我希望此函数接受如下内容：

hello world "SOme quote"

输出应该是：

hello
world
"some quote"

或者如果输入是：

hello world no quote

输出应为：

hello
world
no
quote

但是现在，我得到：

Hello
WOrld
"Hello World"
*** glibc detected *** ./a.out: free(): invalid next size (fast): 0x0000000001760010 ***
a.out: malloc.c:2451: sYSMALLOc: Assertion `(old_top == (((mbinptr) (((char *) &((av)->bins[((1) - 1) * 2])) - __builtin_offsetof (struct malloc_chunk, fd)))) && old_size == 0) || ((unsigned long) (old_size) >= (unsigned long)((((__builtin_offsetof (struct malloc_chunk, fd_nextsize))+((2 * (sizeof(size_t))) - 1)) & ~((2 * (sizeof(size_t))) - 1))) && ((old_top)->size & 0x1) && ((unsigned long)old_end & pagemask) == 0)' failed.
Aborted (core dumped)

看起来输出是对的，但之后就搞砸了
代码是：

int process_command(char command[80]){
char curr_char;
char *word;
int start_pos;
int i;
int len;
len = strlen(command);
for(i=0,start_pos=0;i<strlen(command);i++){
    curr_char = command[i];
    if (curr_char == ' '){
        if (command[i-1]==' ') {start_pos++;continue;}
        word = malloc(i-start_pos*(sizeof(char)));
        strncpy(word,command+start_pos,i-start_pos);
        printf("%s\n",word);
        free(word);

        start_pos =i+1;

    }
    else if (curr_char == '\"'){
        word= malloc(len-i*(sizeof(char)));
        strncpy(word,command+i,len);
        printf("%s\n",word);
        free(word);
        i=len+len;
    }

}

return 0;
}
int main(){
    char buffer[80] = "Hello   WOrld  \"Hello World\"";
    process_command(buffer);
    return 0;
}

问题解决了！谢谢
更新后的代码如下：

int process_command(char command[80]){
char curr_char;
char *word;
int start_pos;
int i;
int len;
int quote=0;
len = strlen(command);
for(i=0,start_pos=0;i<strlen(command);i++){
    curr_char = command[i];
    if (curr_char == ' '){      /*If there was a space found copy the stuff before the space*/
        if ( i>0 && command[i-1]==' ') {
            start_pos++;
            continue;
        }
        word = malloc(i-start_pos+1*(sizeof(char)));
        strncpy(word,command+start_pos,i-start_pos);
        word[i-start_pos+1]='\0';
        printf("%s\n",word);
        free(word);
        start_pos =i+1;

    }
    else if (curr_char == '\"'){        /*If a quote was found, copy the rest of the string and exit loop*/
        word= malloc(len-i+1*(sizeof(char)));
        strncpy(word,command+i,len-i);
        word[len-i+1]='\0';
        printf("%s\n",word);
        free(word);
        quote=1;
        break;
    }

}if (quote==0){                 /*If there was no quote in the string, get the last element*/
    word = malloc(len-start_pos+1*(sizeof (char)));
    strncpy(word,command+start_pos,len-start_pos);
    word[len-start_pos+1]='\0';
    printf("%s\n",word);
        free (word);
    }
    return 0;
}
int main(){
    char buffer[80] = "Hello   \"WOrld  test\"";
    process_command(buffer);
    return 0;
}

但是，我想知道这是否是一种有效的标记化方法？
这是处理用户键入的指令。所以如果用户键入

add 1 2 "SOme text"

我想将查询标记为三个部分，然后对其进行处理。为此，我将它标记化，并将它们放入一个队列中，在稍后的时间，我可以逐个弹出项目并对其进行处理。

最佳答案

你必须确保为你要做的strncpy分配足够的内存。
这两行被一个关闭，因为strncpy也会写入零字节：

word = malloc(i-start_pos*(sizeof(char)));
strncpy(word,command+start_pos,i-start_pos);

这两行毫无意义：分配len-i字节，然后向其写入len字节（加上零字节）：

word = malloc(len-i*(sizeof(char)));
strncpy(word,command+i,len);

关于c - C中奇怪的malloc错误，将单词分词，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/11320987/