Error while executing exec loader.sce

error

addinter(libbuild_lib_path + filesep() + 'libbuild_lib' + getdynlibext(), 'libbuild_lib', list_functions);
Link failed for dynamic library '/home/dhanraj/gsoc/scilab/scilab/scilab/modules/sha256//libbuild_lib.so'.
An error occurred: /home/dhanraj/gsoc/scilab/scilab/scilab/modules/sha256//libbuild_lib.so: undefined symbol: sha256
Link failed for dynamic library '/home/dhanraj/gsoc/scilab/scilab/scilab/modules/sha256//libbuild_lib.so'.
An error occurred: /home/dhanraj/gsoc/scilab/scilab/scilab/modules/sha256//libbuild_lib.so: undefined symbol: sha256
at line    15 of executed file /home/dhanraj/gsoc/scilab/scilab/scilab/modules/sha256/loader.sce

addinter: The shared archive was not loaded: (null)

getSHA256

#include "stdio.h"
#include "string.h"
#include "stdlib.h"
#include "openssl/sha.h"
#include "api_scilab.h"
#include "Scierror.h"
#include "sha256.h"
 
char* getSHA256(char *fname, void* pvApiCtx)
{    
    SciErr sciErr;
    
    ////////// Variables declaration //////////
    int *piAddressVarOne = NULL;
    char *string = NULL;
    char *hash = NULL;
    int iRet = 0;
    
    CheckInputArgument(pvApiCtx, 1, 1) ;
    CheckOutputArgument(pvApiCtx, 1, 1) ;
    
    sciErr = getVarAddressFromPosition(pvApiCtx, 1, &piAddressVarOne);
    if (sciErr.iErr)
    {
        printError(&sciErr, 0);
        return 0;
    }
    
    if ( !isStringType(pvApiCtx, &piAddressVarOne))
    {
        Scierror(999, _("%s: Wrong type for input argument #%d: String expected.\n"),fname , 1);
        return 0;
    }
    
    //printf("Enter String :");
    //scanf("%s",&string);
    
    /*sciErr = getMatrixOfString(pvApiCtx, piAddressVarOne,&m1,&n1,&lenStVarOne,&pStVarOne);
    if(sciErr.iErr)
    {
        printError(&sciErr, 0);
        return 0;
    } 
*/
    if(isScalar(pvApiCtx, piAddressVarOne))
    {
        iRet = getAllocatedSingleString(pvApiCtx, piAddressVarOne, &string);
        if(iRet)
        {
            freeAllocatedSingleString(string);
            return iRet;
        }
        hash = sha256(&string);
        iRet = createSingleString(pvApiCtx, nbInputArgument(pvApiCtx) + 1, hash);
        if(iRet)
        {
            freeAllocatedSingleString(hash);
            return iRet;
        }
    }
    
    /* alloc string */
    //pStVarOne = (char*)MALLOC(sizeof(char)*(lenStVarOne + 1));
    /* get string One */
    /*
    sciErr = getMatrixOfString(pvApiCtx, piAddressVarOne,&m1,&n1,&lenStVarOne,&pStVarOne);
    if(sciErr.iErr)
    {
        printError(&sciErr, 0);
        return 0;
    } 
    */
    
    AssignOutputVariable(pvApiCtx, 1) = nbInputArgument(pvApiCtx) + 1;
    ReturnArguments(pvApiCtx);

    return 0;
    
}

scilab code

files=["getSHA256.c"];
// TODO: WTF ?
WITHOUT_AUTO_PUTLHSVAR = %t;
ilib_build('build_lib',['sha256','getSHA256'],files,[]);
exec loader.sce

sha256.c

/* ==================================================================== */
/* SHA256 Function */
/* This file is released under the 3-clause BSD license. See COPYING-BSD. */
/* ==================================================================== */
#include "string.h"
#include "stdlib.h"
#include "openssl/sha.h"
#include "api_scilab.h"
/* ==================================================================== */
char* sha256(char *string) {
    
    unsigned char digest[SHA256_DIGEST_LENGTH];
    //const char* string ="gsoc";
    
    //printf("Enter String :");
    //scanf("%s",&string);
    
    SHA256_CTX ctx;
    SHA256_Init(&ctx);
    SHA256_Update(&ctx, string, strlen(string));
    SHA256_Final(digest, &ctx);
 
    static char mdString[SHA256_DIGEST_LENGTH*2+1];
    for (int i = 0; i < SHA256_DIGEST_LENGTH; i++)
        sprintf(&mdString[i*2], "%02x", (unsigned int)digest[i]);
 
    return (char *)mdString;
    
}
/* ==================================================================== */

sha256.h

/* ==================================================================== */
/* This file is released under the 3-clause BSD license. See COPYING-BSD. */
/* ==================================================================== */

/**
* multiplybypi function
* @param[in] string a character pointer
* @return SHA256 hash value of input string
*/
char* sha256(char *String);