Thread: pointer from integer without cast

sup people, i'm making a medium project ( around 2k lines of code), and everything seems to work fine, except some warning in the compile (gcc) that tell me i'm making pointers from integer without cast.

i really can't understand why, i'll try to post some snippet to allow you to see if something seems to be faulty.

error is raised on the initialization of a buffer, a struct i declared that is of type buffer_t.

buffer is a pointer to a buffer_t struct, so is of type buffer_t*. the function to initialize this buffer is buffer_init, that takes as parameter an unsigned int and returns a buffer_t*.

this line of code raises the warning "makes pointer from integer without cast".

Code:

 buffer = buffer_init(1)

so i'm declaring the buffer_t* buffer as the result of buffer_init, that returns the pointer to the struct buffer_t.

here it is the buffer_init method:

Code:

buffer_t* buffer_init(unsigned int maxsize) {
    

    int bufferid = shmget(ftok("buffer.c", 'B'), sizeof(buffer_t), IPC_CREAT | 0666);
    if(bufferid == -1) {
        perror("error in allocation of buffer shared memory. \n"); exit(-13);
    }

    int new_message_id = shmget(ftok("buffer.c", 'A'), maxsize*sizeof(msg_t), IPC_CREAT | 0666);
    if(new_message_id == -1) {
        perror("error in allocation of msg_t array. \n"); exit(-14);
    }

    int text_id=shmget(ftok("buffer.c", 'T'), maxsize * TEXT_SIZE, IPC_CREAT|0666);
    if(text_id==-1)
        perror("shmget dell'array text fallito");
    

    int sem_id = semget(ftok("buffer.c", 'S'), 4, IPC_CREAT | 0666);


    buffer_t* new_buffer = (buffer_t*) shmat(bufferid,NULL, 0);
    msg_t* new_message = (msg_t*) shmat(new_message_id, NULL, 0);

    if((sem_initialize(sem_id, maxsize))== -1) {
        perror("semctl() fails to inizialize semaphores."); exit(-3);
    }

    new_buffer->text_array_id = text_id;

    new_buffer->D=0;
    new_buffer->T=0;
    new_buffer->dimension = maxsize;
    new_buffer->msgbuffer = new_message;
    new_buffer->id_sem = sem_id;
    new_buffer->shid_buffer = bufferid;
    new_buffer->shid_msg = new_message_id;
    new_buffer->text_array=(char*)shmat(text_id,NULL,0);

    return new_buffer;
}

lot of the stuff is regarding ipc setup for process communication.

any hint?

PS: ive seen including <string.h> is necessary, i included it in all the source files with no luck.

Since the typedef is already a pointer, should you really be declaring buffer_t* buffer (i.e. a struct buffer_t **)? I would have thought buffer_t buffer would be want you want.

PS This is why, in general but not all cases, I hate typedefs... especially of this type.

Does buffer_t* buffer_init(unsigned int maxsize) have a prototype in scope?

It would help if you also posted your error messages, exactly as they appear in your development environment.


Jim

Originally Posted by Hodor

Does buffer_t* buffer_init(unsigned int maxsize) have a prototype in scope?

that was the issue, thanks!