gmp 4.2.4 - mpf_add two large negative floats - strange result

[Bruce M. Axtens]

G'day everyone,

I'm summing two negative floats:

    char * lhs = "-2234.6016114467412141";
    char * rhs = "-4939600281397002.2812";

According to Perl, using bignum and Math::BigFloat, the answer is

    -4939600281399236.8828114467412141

However, according to GMP, using the code below, the answer is

    -4939600281399236.88281 

Where have I gone wrong? What happened to the remaining "14467412141"?

Kind regards,
Bruce

    #include "stdafx.h"
    #include "gmp-static\gmp.h"
    #include <stdlib.h>         /* For _MAX_PATH definition */
    #include <stdio.h>
    #include <malloc.h>
    #include <math.h>

    #define F(x) mpf_t x; mpf_init( x );

    void main(void)
    {
        F(f_lhs);
        F(f_rhs);
        F(f_res);

        char * resbuff;

        mp_exp_t exp;

        char * lhs = "-2234.6016114467412141";
        char * rhs = "-4939600281397002.2812";

        int validOp = mpf_set_str( f_lhs, lhs, 10 );
        validOp = mpf_set_str( f_rhs, rhs, 10 );

        mpf_add( f_res, f_lhs, f_rhs );
       
        resbuff = mpf_get_str( NULL, &exp, 10, 0, f_res );
        printf( "Using mpf_add, %s + %s = %s (exp=%d)\n", lhs, rhs,
    resbuff, exp );
       
        free(resbuff);
    }

Sample output:

    Using mpf_add, -2234.6016114467412141 + -4939600281397002.2812 =
    -493960028139923688281 (exp=16)






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