The structure begins with job interface routines. The first function builds a definition of the work area for use by the Adobe PDF Library. This is a single data structure named PDFLDataRec, which must be created in the user space prior to initializing the Library. For the duration of the usage of the Library, it must persist in memory. If local memory allocation routines are to be used in place of the built-in routines, pointers to those routines must be placed into the record.
| Order | Method | Description |
| 1 | PDFLDataRec(Client, Size) | A single data structure which defines the work area to be used by the Library. |
| 2 | AsMemAllocProc(Client, Size) | When used, this call instructs the Library to use the named client rather than alloc() to obtain access to memory. |
| 3 | AsMemReallocProc(Client, Size) | When used, this call instructs the Library to use the named client rather than realloc() to increase the size of a memory block. |
| 4 | AsMemFreeProc(Client, Size) | When used, this call instructs the Library to use the named client rather than free() to return memory to the pool. |
| 5 | AsMemAvailProc(Client, Size) | When used, this call instructs the Library to use the named client rather than avail() to test for the availability of memory. |
| 6 | PDFLInitHFT(PDFLData*) | This call initializes the Library for usage. The PDFLData declaration refers to an area of memory which the Library may use as a work area. There must be exactly one of these calls prior to any other call to the Library. |
| 7 | PDFLTermHFT() | Terminates the Library and frees all resources used by the Library. No other calls to the Library may follow this call. |
| 8 | PDFLGetVersion() | Test for compatibility of the version of the Library used when the executable was created, including the version used at run time. Results indicate that it is either the same, previous, or later version. |