string to file? help?

[cablet]

Greetings,
I have created a unix program that converts a targa file to a YUV video file. I used unsigned char*'s to handle the file data. I can read large files into my char*'s but am unable to put those large char*'s back into a file. If the file is small (80K) there is no problem writing to file. But when I try 1.1 megs (which is my goal) the new file size is 1 byte (the first byte of the char pointer).

Question:
How can I write a large unsigned char* to a newly created file? I can currently read in large files but not write to a new one. I have tried setbuf() as well as fputc() in a loop but either way my file size is 1. (unless the original data is less then about 133kb).

here is a sample of what I am trying. yuv is my unsigned char *
please presume that memory and variables have been correctly allocated or declared

/****** code sample ********/

unsigned char* tempPtr;
if( (Nfp = fopen(newfile, "w" )) == NULL)
{
printf("Problem creating new file!\n");
exit(1);
}

fseek(Nfp,0,SEEK_SET);
for(x=0;x<w*h*2;x++); //w*h*2 is the length of yuv
{
tempPtr = yuv + x;
fputc(*tempPtr,Nfp);
} */

close(Nfp);


any ideas would greatly help
thanks
cablet

[Sebastiani]

Well, you have a semicolen at the end of the for loop. That may be a typo, though. Anyway, I would personally use fwrite since this means just one call:

fwrite(yuv, sizeof(unsigned char), w*x*2, Nfp);

Also, you can just use the pointer...

tempPtr = yuv;

for( x = 0; x < (w*h*2); x++ )  {
 fputc(*tempPtr,Nfp);  
 tempPtr++;
 //...fputc(*(tempPtr++), Nfp);  
 }

Other than that, it looks OK. Post more code if the problem persists...