ISO C++ forbids comparison between pointer and integer [-fpermissive]

sworsman31415926發表於2020-12-25
C++ORB

shmwrite.cpp:67:9: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   67 |  if(shm == -1)
void *shm = NULL;

    //建立共享記憶體
    shmid = shmget((key_t)1234,sizeof(struct shared_use_st),0666|IPC_CREAT);
    if(shmid == FAIL_VALUE)
    //if(shm == -1)
    {
        fprintf(stderr,"shmget failed\n");
        exit(EXIT_FAILURE);
    }

看錯變數了。和-1直接可以比較大小的。

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