Hi, I have a probelm with fwrite function. I use it to write large chunk of binary data to 24-bit bitmap(.bmp) files of resolution 2400x1500. In the program below, I read an image 1700.bmp and write the same to 1.bmp. I perform this infinite number of times. At the beginning, the writting is fast. But after about 25 images, the writting becomes too slow. When I remove the fwrite statement, the program executes very fast. So fwrite is the culprit. But I have to make the program run fast and at the same speed. Why is this problem caused and how to rectify it? I have copied the program below: Code: #include <stdio.h> #include<conio.h> #include<stdint.h> struct MagicNumber { unsigned char type[2]; }BmpMN; struct INFOHEADER { unsigned int sizeByte; unsigned short reserved1; unsigned short reserved2; unsigned int offsetbits; unsigned int sizeHeader; int width; int height; unsigned short planes; unsigned short bitcount; unsigned int compression; unsigned int sizeImage; int xpelspermeter; int ypelspermeter; unsigned int colorsused; unsigned int colorsimportant; } BitmapInfoHeader; int main() { FILE *ip,*op; int i=1; uint8_t buff[1500][2400*3]; while(1) { printf("Reading %d\n",i); ip=fopen("op/1700.bmp","rb"); op=fopen("op/1.bmp","wb"); fread(&BmpMN,sizeof(BmpMN),1,ip); fread(&BitmapInfoHeader,sizeof(BitmapInfoHeader),1,ip); fread(&buff,sizeof(buff),1,ip); fwrite(&BmpMN,sizeof(BmpMN),1,op); fwrite(&BitmapInfoHeader,sizeof(BitmapInfoHeader),1,op); //This statement is executed slower from 26th image onwards fwrite(&buff,sizeof(buff),1,op); fclose(ip); fclose(op); i++; fflush(&buff); } return 0; } Thank you
