Question

我正在尝试在MINIX3上运行一个C / C ++应用程序，该应用程序应该使用msg.h使用msgsnd（）和msgget（）在两个进程之间发送消息。

这是我得到的错误：

send.cpp:(.text+0x7f): undefined reference to `msgget'
send.cpp:(.text+0x1c1): undefined reference to `msgsnd'
clang: error: linker command failed with exit code 1 (use -v to see invocation)

我使用clang ++编译代码：

clang++ send.cpp -o send.out

这是send.cpp代码：

#include <lib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MSGSZ     128
/*
* Declare the message structure.
*/

typedef struct msgbufer {
    long    mtype;
    char    mtext[MSGSZ];
} message_buf;

int main()
{
    int msqid;
    int msgflg = IPC_CREAT | 0666;
    key_t key;
    message_buf sbuf;
    size_t buf_length;

    /*
    * Get the message queue id for the
    * "name" 1234, which was created by
    * the server.
    */
    key = 1234;

    (void)fprintf(stderr, "\nmsgget: Calling msgget(%i,\
                          %#o)\n",
                          key, msgflg);

    if ((msqid = msgget(key, msgflg)) < 0) {
        perror("msgget");
        exit(1);
    }
    else
        (void)fprintf(stderr, "msgget: msgget succeeded: msqid = %d\n", msqid);


    /*
    * We'll send message type 1
    */

    sbuf.mtype = 1;

    (void)fprintf(stderr, "msgget: msgget succeeded: msqid = %d\n", msqid);

    (void)strcpy(sbuf.mtext, "Hello other process 2.");

    (void)fprintf(stderr, "msgget: msgget succeeded: msqid = %d\n", msqid);

    buf_length = strlen(sbuf.mtext) + 1;



    /*
    * Send a message.
    */
    if (msgsnd(msqid, &sbuf, buf_length, IPC_NOWAIT) < 0) {
        printf("%d, %li, %s, %lu\n", msqid, sbuf.mtype, sbuf.mtext, buf_length);
        perror("msgsnd");
        exit(1);
    }

    else
        printf("Message: \"%s\" Sent\n", sbuf.mtext);

    exit(0);
}

Answer 1

您没有链接包含msgsnd和msgget函数的库，因此您的链接器步骤失败。我不熟悉Minix，所以我不确定库的存储位置或所谓的库。基本上，您需要在链接步骤中使用-l<msg>标记。其中<msg>是包含实现的库的名称。

clang：错误：链接器命令失败，退出代码为1（使用-v查看调用）MINIX3

1 个答案: