LIBPNG: Read Error

[Nofico]

下面的代码在两个叹号行包围的代码那里停下，屏幕输出：libpng: Read error。我可真不明白了，明明是原封不动地抄官方的example.c，竟然不能编译通过？准确地说，png_read_row都会出错。

#include <stdio.h>
#include <stdlib.h>
#include "png.h"
#include <assert.h>

	FILE*fp=fopen(fileName,"rb");
	assert(fread(cpBuf,sizeof(char),BYTES_TO_CHECK,fp)==BYTES_TO_CHECK);
	assert(!png_sig_cmp(cpBuf,0,BYTES_TO_CHECK));;
	png_ptr=png_create_read_struct(PNG_LIBPNG_VER_STRING,NULL,NULL,NULL);
	info_ptr=png_create_info_struct(png_ptr);
	end_info=png_create_info_struct(png_ptr);

	/*Setting up error handling.*/
	if(setjmp(png_jmpbuf(png_ptr))){
		png_destroy_read_struct(&png_ptr,&info_ptr,&end_info);
		fclose(fp);
		return NULL;
	}
	rewind(fp);
	png_init_io(png_ptr,fp);
	png_read_png(png_ptr,info_ptr,PNG_TRANSFORM_EXPAND|PNG_TRANSFORM_PACKING,NULL);
	width=png_get_image_width(png_ptr,info_ptr);
	height=png_get_image_height(png_ptr,info_ptr);
	bit_depth=png_get_bit_depth(png_ptr,info_ptr);
	color_type=png_get_color_type(png_ptr,info_ptr);

	row_pointers=png_calloc(png_ptr, height*width*bit_depth);
	assert(row_pointers!=NULL);
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
	png_read_rows(png_ptr,row_pointers,NULL,height);
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

        png_destroy_read_struct(&png_ptr,&info_ptr,&end_info);
	fclose(fp);