readv

長さが違う３個の読み込み用バッファを用意して、readvで読み込む。

#include < sys/uio.h >
#include < stdio.h >

int main()
{
    int i;
    ssize_t n;
    char buf1[5], buf2[10], buf3[15];
    struct iovec vector[3];
    
    vector[0].iov_base = buf1;
    vector[0].iov_len = sizeof buf1;
    
    vector[1].iov_base = buf2;
    vector[1].iov_len = sizeof buf2;
    vector[2].iov_base = buf3;
    vector[2].iov_len = sizeof buf3;
    
    if ((n = readv(0,vector, 3)) < 0){
        perror("readv");
        return 1;
    }
    
    for (i = 0; i < 3; i++){
        if (n < vector[i].iov_len){
            vector[i].iov_len = n;
        }
        n -= vector[i].iov_len;
            
            printf("buf%d[] = %.*s\n",
                   i, (int)vector[i].iov_len, (char *)vector[i].iov_base);
        }
        return 0;
}