mygetline 实现

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

ssize_t mygetline(char **lineptr, size_t *n, FILE *stream)
{
	if(*lineptr==NULL){
		*n=50;
		*lineptr=malloc(*n);
	}
	int ch;
	int i=0;
	while(1){
			ch=fgetc(stream);
			if(ch==EOF)
					return -1;
			if(i > *n){
					*n+=50;
					*lineptr=realloc(*lineptr,*n);
			}
			*(*lineptr+i)=ch;
			i++;

			if(ch=='\n'){
				*(*lineptr+i)='\0';
				return i;
			}
	}
	return i;
}

void mygetline_free(char **lineptr)
{
	if(*lineptr != NULL)
	{
		free(*linefree);
	}
}


int main(int argc,char **argv)
{
	FILE *fp;
	char *line = NULL;
	size_t line_size = 0;
	
	if(argc < 2)
	{
		fprintf(stderr,"Usage...\n");
		exit(1);
	}

	fp = fopen(argv[1],"r");
	if(fp == NULL)
	{
		perror("fopen()");
		exit(1);
	}


	while(1)
	{
		if(mygetline(&line,&line_size,fp) < 0)
			break;
		
		printf("line_size = %d\n",line_size);
		printf("%d\n",strlen(line));
		printf("%s\n",line);
	}

	fclose(fp);

	mygetline_free(line);

	exit(0);
}