recv返回值问题和在while(recv（）)的返回值不一样

if ((select(sockfd + 1), &readfd, NULL, NULL, &stime) > 0)
{
    #if 1
    nlen = recv(sockfd, pcBuffer, 199, 0);
    printf("recv num(%d), buffer num(%d).\n", nlen, lRecvnum);
    if ((lRecvnum + nlen) < 199)
    {
        lRecvnum += nlen;
        pcBuffer += nlen;
        printf("recv num(%d), buffer num(%d), buffer(%s).\n", nlen, lRecvnum, buf);
    }
    #else
    while ((nlen = recv(sockfd, pcBuffer, 199, 0)) > 0)
    {
        printf("recv num(%d), buffer num(%d).\n", nlen, lRecvnum);
        if ((lRecvnum + nlen) < 199)
        {
            Recvnum += nlen;
            pcBuffer += nlen;
            printf("recv num(%d), buffer num(%d), buffer(%s).\n", nlen, lRecvnum, buf);
        }
    }
    #endif
}

现在想问的是执行上面一段代码，就是#if 1，recv返回的值是正常的，返回值是199跟写到pcBuffer的数据是一样的，但是如果把#if 1改成#if 0，执行下面在
while ((nlen = recv(sockfd, pcBuffer, 199, 0)) > 0)的代码分支的时候，recv的返回值一直是1，但是写到pcBuffer的数据却是正确的，这个是为什么？recv的返回值是1，但是写到pcBuffer中的个数却不是1，而是正确的个数，为什么这个时候的recv不返回不跟#if 1的时候是一样的，也是199？

按正确的逻辑
while ((nlen = recv(sockfd, pcBuffer, 199, 0)) > 0)这个应该改为

Recvnum = 0;
while ((nlen = recv(sockfd, pcBuffer, 199- Recvnum, 0)) <199)
{
}

tf("recv num(%d), buffer num(%d).\n", nlen, lRecvnum);
if ((lRecvnum + nlen) < 199)
{
lRecvnum += nlen;
pcBuffer += nlen;
printf("recv num(%d), buffer num(%d), buffer(%s).\n", nlen, lRecvnum, buf);
}
#else
while ((nlen = recv(sockfd, pcBuffer, 199, 0)) > 0)
{
printf("recv num(%d), buffer num(%d).\n", nlen, lRecvnum);
if ((lRecvnum + nlen) < 199)

tf("recv num(%d), buffer num(%d).\n", nlen, lRecvnum);
if ((lRecvnum + nlen) < 199)
{
lRecvnum += nlen;
pcBuffer += nlen;
printf("recv num(%d), buffer num(%d), buffer(%s).\n", nlen, lRecvnum, buf);
}
#else
while ((nlen = recv(sockfd, pcBuffer, 199, 0)) > 0)
{
printf("recv num(%d), buffer num(%d).\n", nlen, lRecvnum);
if ((lRecvnum + nlen) < 199)