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c - 预处理器编译错误#error

问题描述

我使用 Makefile 编译项目，但在编译“amqp_soket.c”文件期间收到此错误：如何解决此错误。请问有什么建议吗？

amqp_socket.c: 在函数'amqp_poll'中: amqp_socket.c:261:2: 错误: #error "poll() or select() is required to compile rabbitmq-c" #error "poll() or select() is required编译rabbitmq-c"

amqp_socket.c：在函数“amqp_poll”中：amqp_socket.c:263:1：警告：控制到达非无效函数的结尾[-Wreturn-type]

int amqp_poll(int fd, int event, amqp_time_t deadline) {
#ifdef HAVE_POLL
  struct pollfd pfd;
  int res;
  int timeout_ms;

  /* Function should only ever be called with one of these two */
  assert(event == AMQP_SF_POLLIN || event == AMQP_SF_POLLOUT);

start_poll:
  pfd.fd = fd;
  switch (event) {
    case AMQP_SF_POLLIN:
      pfd.events = POLLIN;
      break;
    case AMQP_SF_POLLOUT:
      pfd.events = POLLOUT;
      break;
  }

  timeout_ms = amqp_time_ms_until(deadline);
  if (-1 > timeout_ms) {
    return timeout_ms;
  }

  res = poll(&pfd, 1, timeout_ms);

  if (0 < res) {
    /* TODO: optimize this a bit by returning the AMQP_STATUS_SOCKET_ERROR or
     * equivalent when pdf.revent is POLLHUP or POLLERR, so an extra syscall
     * doesn't need to be made. */
    return AMQP_STATUS_OK;
  } else if (0 == res) {
    return AMQP_STATUS_TIMEOUT;
  } else {
    switch (amqp_os_socket_error()) {
      case EINTR:
        goto start_poll;
      default:
        return AMQP_STATUS_SOCKET_ERROR;
    }
  }
  return AMQP_STATUS_OK;
#elif defined(HAVE_SELECT)
  fd_set fds;
  fd_set exceptfds;
  fd_set *exceptfdsp;
  int res;
  struct timeval tv;
  struct timeval *tvp;

  assert((0 != (event & AMQP_SF_POLLIN)) || (0 != (event & AMQP_SF_POLLOUT)));
#ifndef _WIN32
  /* On Win32 connect() failure is indicated through the exceptfds, it does not
   * make any sense to allow POLLERR on any other platform or condition */
  assert(0 == (event & AMQP_SF_POLLERR));
#endif

start_select:
  FD_ZERO(&fds);
  FD_SET(fd, &fds);

  if (event & AMQP_SF_POLLERR) {
    FD_ZERO(&exceptfds);
    FD_SET(fd, &exceptfds);
    exceptfdsp = &exceptfds;
  } else {
    exceptfdsp = NULL;
  }

  res = amqp_time_tv_until(deadline, &tv, &tvp);
  if (res != AMQP_STATUS_OK) {
    return res;
  }

  if (event & AMQP_SF_POLLIN) {
    res = select(fd + 1, &fds, NULL, exceptfdsp, tvp);
  } else if (event & AMQP_SF_POLLOUT) {
    res = select(fd + 1, NULL, &fds, exceptfdsp, tvp);
  }

  if (0 < res) {
    return AMQP_STATUS_OK;
  } else if (0 == res) {
    return AMQP_STATUS_TIMEOUT;
  } else {
    switch (amqp_os_socket_error()) {
      case EINTR:
        goto start_select;
      default:
        return AMQP_STATUS_SOCKET_ERROR;
    }
  }
#else
#error "poll() or select() is needed to compile rabbitmq-c"
#endif
}

标签： cmakefile

解决方案

您可以使用 -D 和 CFLAGGS 在源代码中定义宏。

make CFLAGS=-DHAVE_POLL

现在

#ifdef HAVE_POLL

变成真的

编辑

还要检查 Makefile 本身是否使用 $(CFLAGS) 作为参数

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