#include <stdio.h>
#include <FastCRC.h>

#define BUFF_SIZE  1024

int main()
{
    FILE* file;
    unsigned char buff[ BUFF_SIZE ];
    unsigned long crcvar;
    unsigned long checksum;

    file = fopen( "c:\\Test.txt", "rb" );

    if( file == NULL )
        return 1;

    /*****Initialize the crcvar before calling Update and Final*****************/

    SL_FCRC32_Init( &crcvar );

    /*****Calculate the checksum by calling Update for each block of the file***/

    while( !feof( file ) )
    {
        unsigned int nCount = fread( buff, sizeof( char ), BUFF_SIZE, file );
        SL_FCRC32_Update( &crcvar, buff, nCount );
    }

    /*****Do final changes and get the checksum*********************************/

    checksum = SL_FCRC32_Final( &crcvar );

    /*****Use the checksum******************************************************/
    /*...*/

    fclose( file );

    return 0;
}