LinuxQuestions.org - why cann't the getchar() return?

hi all
i just want to get a char from getchar(),but the getchar never return regardless how many characters i input and hit enter

here is the program i encounter the problem:

Code:

int main(int argc, char **argv){

    int qid;

    int pid;

    int i;

    key_t key;

    int len;

    struct message msg;

    struct message childMsg;

    char sel;

    if((key=ftok(".",'a')) == -1){

        perror("ftok");

        exit(1);

    }

    if((qid=msgget(key,IPC_CREAT|0666)) == -1){

            perror("msgget");

            return -1;

    }

    printf("get msgQueue:%d\n",qid);

    for(i=0; i<5; i++){

        puts("please enter the message to the queue");

        if((fgets(msg.msg_text,BUFSZ,stdin))==NULL){

            perror("fgets");

            exit(1);

        }

        msg.msg_type = i+1;

        len = strlen(msg.msg_text);

        if(msgsnd(qid,&msg,len,0) < 0){

            perror("message send");

            exit(1);

        }

    }

    printf("please select the message id you want to get:\n");



    for(i=0; i<5; i++){

            sel = getchar();

            if(msgrcv(qid,&childMsg,BUFSZ,sel-'a'+1,0)<0){

                perror("msgrcv");

                exit(1);

            }

            printf("the message is %s\n",childMsg.msg_text);

        }

        exit(0);

}

when the program run to getchar(), i input a char and hit enter, but i doesn't return....

what's the problem? thanks in advance