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.

<source lang="cpp">#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);
  }</source>