C Tutorial/stdio.h/ftell
ftell
Item Value Header file stdio.h Declaration long int ftell(FILE *stream); Function returns the value for the file position pointer. Valid for binary file and invalid for text file. Return returns -1 on failure.
#include <stdio.h>
#include <stdlib.h>
int main(void){
FILE *fp;
if((fp=fopen("test", "rb")) == NULL) {
printf("Cannot open file.\n");
exit(1);
}
int i;
if((i=ftell(fp)) == -1L)
printf("A file error has occurred.\n");
fclose(fp);
}