There are routines which provide FORTRAN-callable methods for file handling; it is not normally necessary to use these routines for reading BUFR or GRIB products.
| PBSEEK | To position a file |
| PBREAD | To read a given number of bytes from a file |
| PBREAD2 | To read a given number of bytes from a file (different behaviour from PBREAD on end-of-file) |
| PBWRITE | To write a given number of bytes to a file |
| PBTELL | To tell the current byte offset in a file. |
These subroutines are written in C and use standard C library functions for file handling (fopen, fclose, fseek, fread and fwrite).