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(gmp.info)Converting Integers

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Conversion Functions
====================

   This section describes functions for converting GMP integers to
standard C types.  Functions for converting _to_ GMP integers are
described in Note: Assigning Integers and Note: I/O of Integers.

 - Function: unsigned long int mpz_get_ui (mpz_t OP)
     Return the least significant part from OP.  This function combined
     with
     `mpz_tdiv_q_2exp(..., OP, CHAR_BIT*sizeof(unsigned long int))' can
     be used to decompose an integer into unsigned longs.

 - Function: signed long int mpz_get_si (mpz_t OP)
     If OP fits into a `signed long int' return the value of OP.
     Otherwise return the least significant part of OP, with the same
     sign as OP.

     If OP is too large to fit in a `signed long int', the returned
     result is probably not very useful.  To find out if the value will
     fit, use the function `mpz_fits_slong_p'.

 - Function: double mpz_get_d (mpz_t OP)
     Convert OP to a `double'.

 - Function: double mpz_get_d_2exp (signed long int EXP, mpz_t OP)
     Find D and EXP such that D times 2 raised to EXP, with
     0.5<=abs(D)<1, is a good approximation to OP.

 - Function: char * mpz_get_str (char *STR, int BASE, mpz_t OP)
     Convert OP to a string of digits in base BASE.  The base may vary
     from 2 to 36.

     If STR is `NULL', the result string is allocated using the current
     allocation function (Note: Custom Allocation).  The block will be
     `strlen(str)+1' bytes, that being exactly enough for the string and
     null-terminator.

     If STR is not `NULL', it should point to a block of storage large
     enough for the result, that being `mpz_sizeinbase (OP, BASE) + 2'.
     The two extra bytes are for a possible minus sign, and the
     null-terminator.

     A pointer to the result string is returned, being either the
     allocated block, or the given STR.

 - Function: mp_limb_t mpz_getlimbn (mpz_t OP, mp_size_t N)
     Return limb number N from OP.  The sign of OP is ignored, just the
     absolute value is used.  The least significant limb is number 0.

     `mpz_size' can be used to find how many limbs make up OP.
     `mpz_getlimbn' returns zero if N is outside the range 0 to
     `mpz_size(OP)-1'.