Feof Ferror Clearerr Fileno return status information of files #include <stdio.h> feof FILE *fp ferror FILE *fp clearerr FILE *fp fileno FILE *fp Feof returns non-zero if the file associated with "fp" has reached its end. Zero is returned on error. Ferror returns non-zero if an error condition occurs on access to the file "fp"; zero is returned otherwise. The error condition persists, preventing further access to the file by other Standard Library functions, until the file is closed, or it is cleared by clearerr. Clearerr resets the error condition on the file "fp". This does NOT "fix" the file or prevent the error from occurring again; it merely allows Standard Library functions at least to try. These functions are actually macros that are defined in "<stdio.h>" so their names cannot be redeclared. System call open(), fopen().