--- name: "libppl_c" section: "3" platform: "linux" package: "ppl" version: "1.2-7" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/libppl_c" --- # libppl\_c(3) the C interface of the Parma Polyhedra Library ## NAME libppl\_c - the C interface of the Parma Polyhedra Library ## SYNOPSIS **#include \** cc file.c **-lppl** ## DESCRIPTION This is a short overview on how to use the Parma Polyhedra Library (PPL) in your C programs on Unix-like operating systems. Note that the PPL has interfaces also for C++, Java, OCaml and a number of Prolog systems: look elsewhere for documentation on those. Note also that the present document does not describe the library functionality, its classes or its methods and functions: see *The Parma Polyhedra Library User's Manual (version 1.2)* and *The Parma Polyhedra Library C Language Interface User's Manual (version 1.2)* for this kind of information. ## INCLUDING THE HEADER FILE The C interface of the PPL has only one header file, named *ppl\_c.h*. So your program should contain a directive of the form **#include \** Of course, you must make sure you installed the PPL in a place where the compiler can find it, either by itself or with the help of a suitable **-Idir** command line option (see the file *INSTALL* for information on how to configure the library so that it is installed in the place of your choice). ## INITIALIZING AND FINALIZING THE LIBRARY In order to initialize the Parma Polyhedra Library you must call the function **int ppl\_initialize(void)** before using any of its functionalities. It is also a good norm to call the function **int ppl\_finalize(void)** when you are done with the library. ## USING THE LIBRARY Keeping in mind that there is no substitute for a careful reading of *The Parma Polyhedra Library User's Manual (version 1.2)* and *The Parma Polyhedra Library C Language Interface User's Manual (version 1.2)* you can find examples of use in the directories **interfaces/C/tests** and **demos/ppl\_lpsol** of the source distribution. ## LINKING WITH THE LIBRARY Linking with the C interface of the Parma Polyhedra Library is best done using the C compiler itself: usually, specifying the **-lppl\_c** command line option is enough. In fact, if you use a shared version of the library, this automatically records the dependency from the PPL core and the GMP libraries, something that the linker ought to deal with gracefully. Otherwise you will have to add **-lppl -lgmpxx -lgmp** to the command line. Things are more complex if you installed the PPL into some nonstandard place. In this case you will have to use the **-Ldir** option and, if you use a shared version of the library, possible take further steps: see the documentation of your system for more information on this subject (the *Program Library HOWTO* is especially valuable for GNU/Linux users). ## RETURN VALUES All the PPL C interface functions return an int: a negative value means that an error occurred. See *The Parma Polyhedra Library C Language Interface User's Manual (version 1.2)* for the error codes. ## IMPLEMENTING MEMORY-GUARDED COMPUTATIONS One of the interesting features of the Parma Polyhedra Library is the possibility to implement memory-guarded computations. The idea is that you can limit the amount of virtual memory available to the process, launch a PPL computation, and be ready to be returned a **PPL\_ERROR\_OUT\_OF\_MEMORY** error code. You can then take the appropriate corrective measures (e.g., simplify the polyhedra and/or select less precise though less complex algorithms), and restart the computation. In order to do that, you should define alternative memory allocation functions for GMP that throw **std::bad\_alloc** upon memory exhaustion. See ***libppl*****(3)** for instructions on how to do that. ## USING NATIVE FLOATING POINT NUMBERS At initialization time, the Parma Polyhedra Library sets the FPU rounding mode in a way that allows its floating-point-based computations to be conservative (i.e., possibly approximated but correct) and reasonably efficient. In case your application itself uses native floating point numbers and relies on a particular rounding mode (if you are in doubt, assume that it does rely on round-to-nearest to be in effect), you should use the function **int ppl\_restore\_pre\_PPL\_rounding()** after the PPL initialization and before using native floating point numbers in the application. If your application does not use any floating-point-based PPL abstraction, no further measure should be taken. Otherwise, it is imperative to call the function **int ppl\_set\_rounding\_for\_PPL()** before invoking any PPL interface related to such abstractions. ## SEE ALSO **[ppl-config(1)](/ppl-config/1.md)** **[libppl(3)](/libppl/3.md)** Roberto Bagnara, Patricia M. Hill, and Enea Zaffanella. *The Parma Polyhedra Library User's Manual (version 1.2)*, available (in several formats) at **http://bugseng.com/products/ppl/** . Roberto Bagnara, Patricia M. Hill, and Enea Zaffanella. *The Parma Polyhedra Library C Language Interface User's Manual (version 1.2)*, available (in several formats) at **http://bugseng.com/products/ppl/** . David A. Wheeler. *Program Library HOWTO*, available (in several formats) at **http://www.dwheeler.com/program-library/** . ## AVAILABILITY The latest version of the Parma Polyhedra Library and all the documentation is available at **http://bugseng.com/products/ppl/** . ## AUTHOR See the file **CREDITS** in the source distribution or use the command **ppl-config --credits** for a list of contributors. ## REPORTING BUGS Report bugs to \. ## COPYRIGHT AND NO WARRANTY Copyright (C) 2001-2010 Roberto Bagnara \ Copyright (C) 2010-2016 BUGSENG srl (http://bugseng.com)\ This is free software; see the file **COPYING** in the source distribution or use the command **ppl-config --copying** to obtain the copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.