C语言按行读入文件

getline() 函数无论一行多长，动态分配内存读入行

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc,const char *argv[])
{
    FILE *fp;
    size_t len = 0;
    char *str = NULL;
    ssize_t read;
    
    if(argc != 2)
    {
        fprintf(stderr,"usage: %s <src>\n",argv[0]);
        exit(1);
    }

    if((fp=fopen(argv[1],"r")) == NULL)
    {
        perror("fopen()");
        exit(1);
    }
    
    while((read = getline(&str,&len,fp)) != -1)
    {
        
        //str[read-1]='\0'; 去掉行末换行符
        fprintf(stdout,"%s",str);
    }
    fclose(fp);

    exit(0);
}