Linux socket client

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/prctl.h>
#include <netinet/tcp.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <errno.h>
#include <ctype.h>

#include "common.h"
#include "message.h"

int safe_send(int __fd, const void *__buf, size_t __n, int __flags) {
    int __snd = 0;
    int __off = 0;
    int __rem = __n;

    while (__rem > 0) {
        __snd = send(__fd, __buf + __off, __rem, __flags);
        if (__snd > 0) {
            __off += __snd;
            __rem -= __snd;
        }
        else if (__snd == -1) {
            perror("send:");
            switch(errno) {
            case EACCES: // not permission
                break;
            case EAGAIN: // The socket is marked nonblocking and the requested operation would block.
                break;
            case EALREADY: // Another Fast Open is in progress.
                break;
            case EBADF: // sockfd is not a valid open file descriptor.
                break;
            case ECONNRESET: // Connection reset by peer
                break;
            case EDESTADDRREQ: // The socket is not connection-mode, and no peer address is set.
                break;
            case EFAULT: // An invalid user space address was specified for an argument.:
                break;
            case EINTR: // A signal occurred before any data was transmitted;
                break;
            case EINVAL: // Invalid argument passed.
                break;
            case ENOBUFS: // The output queue for a network interface was full.
                usleep(10000);
                break;
            case EPIPE: // The local end has been shut down on a connection oriented socket.
                break;
            default:
                break;
            }
        }
    }

    return __off;
}

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

    int                 ret;
    int                 sockfd;
    char                buf[1024];
    struct sockaddr_in  addr;

    sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sockfd == -1) {
        handle_error("socket");
    }

    bzero(&addr, sizeof(addr));
    addr.sin_port = htons(IBOX_PORT);
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    ret = connect(sockfd, (struct sockaddr*)&addr, sizeof(addr));
    if (ret == -1) {
        close(sockfd);
        handle_error("connect");
    }

    bzero(buf, sizeof(buf));
    snprintf(buf, sizeof(buf), "[%d]: hello world\n", getpid());
    ret = safe_send(sockfd, buf, sizeof(buf), 0);
    if (ret > 0) {
        //
    }
    usleep(100000);
    bzero(buf, sizeof(buf));
    snprintf(buf, sizeof(buf), "[%d]: byebye\n", getpid());
    ret = safe_send(sockfd, buf, sizeof(buf), 0);
    if (ret > 0) {
        //
    }

    usleep(100000);
    close(sockfd);

    return 0;
}