FILE*s and changing 4 bytes

Original Post

Dec 7, 2001 at 11:08 AM

i want to change 4 bytes of a file, starting at the 6th byte, leaving the rest of the file intact. here''s what i tried to do:


FILE *f;
f = fopen(filename, "w+b");
fseek(f, 6, SEEK_SET);
unsigned int v = 1;
fwrite(&v, sizeof(v), 1, f);
fclose(f);

problem: that erases the rest of the file. how do i do it w/o erasing the rest of the file?

Dec 7, 2001 at 11:43 AM

You may try this :

FILE * f = fopen( "myFile", "r+b");

Dec 7, 2001 at 11:59 AM

yup, that worked.

i thought about trying that, but assumed that it would throw some sort of error. apparently not!

thanks