I want to integrate my Ada static library (libnewapi.a) with my C source code (main.c). I do not have any issues generating the static library but when trying to link it with main.c. I get the below link error, libnewapi.a(unit1.o):unit1.adb:(.text+0x31): undefined reference to `__gnat_rcheck_CE_Overflow_Check' I am not using this reference in my main.c not in any of my Ada files. I do not know why this reference was added automatically. It is crucial that I need to link my main.c using a static Ada library for my project. I do not know where I am going wrong. Help is much appreciated. Thanks!

I am generating libnewapi.a using a GPR as below,

    -- ada_gen_a.gpr
    project ada_gen_a is
       for Languages use ("Ada");
       for Source_Dirs use ("./");
       for Library_Name use "newapi";
       for Library_Dir use "./Lib/";
       for Library_Kind use "static";

       package Naming is
          for Spec_Suffix ("ada") use ".ads";
          for Body_Suffix ("ada") use ".adb";
          for Separate_Suffix use ".adb";
          for Dot_Replacement use ".";
          for Casing use "mixedcase";
       end Naming;

       Ada_Switches := ("-gnato", "-O2");

       package Compiler is
          for Default_Switches ("ada") use Ada_Switches;
       end Compiler;

       package Binder is
          for Default_Switches ("Ada") use ("-n","-Lada");
       end Binder;
    end ada_gen_a;

Ada Sourcefiles:

    --  unit1.ads
    package Unit1 is
       function Add (A, B : Integer) return Integer;
       pragma Export (C, Add, "ada_add");
    end Unit1;

    -- unit1.adb
    package body Unit1 is
       function Add (A, B : Integer) return Integer is
       begin
          return A + B;
       end Add;
    end Unit1;

C Source File:

    /* main.c */
    #include <stdio.h>
    extern void ada_add (void);
    int main (int argc, char *argv[])
    {
       int a = 21, b = 7, c = 0;
       printf ("%d", a);
       printf ("%d", b);
       c = ada_add(a,b);
       printf ("%d", c);
       return 0;
    }

I am using the below GPR to link the above main.c with the Ada static library generated using ada_gen_a.gpr.

    -- Ada_Use_A.gpr
    with "newapi.gpr";
    project Ada_Use_A is

       for Languages use ("C");
       for Source_Dirs use (".");
       for Source_Files use ("main.c");

       package Naming is
          for Casing use "mixedcase";
       end Naming;

       Ada_Switches := ("-gnato", "-O2");

       package Compiler is
          for Default_Switches ("C") use ("-O2", "-Wall");
          for Default_Switches ("Ada") use Ada_Switches;
       end Compiler;

       package Binder is
          for Default_Switches ("Ada") use ("-n","-Lada");
       end Binder;

       for Main use ("main.c");

    end Ada_Use_A;

    -- newapi.gpr
    project newapi is
       for Externally_Built use "true";
       for Source_Files use ();
       for Library_Dir use ".\lib\";
       for Library_Name use "newapi";
       for Library_Kind use "static";
    end newapi;

When I try to build the Ada_Use_A.gpr GPS I get the below linker error, libnewapi.a(unit1.o):unit1.adb:(.text+0x31): undefined reference to __gnat_rcheck_CE_Overflow_Check' gprbuild: link of main.c failed`