Hi

I wanted to try out the splice syscall. I have this function - it should copy content of one file to another:

static void test_splice( int in, int out ) {

        int i = 0, rcvd = 0;
        int filedes[2];
        off_t off = 0;

        if ( pipe( filedes ) < 0 ) {
                perror( "Kicha pipe" );
                exit( EXIT_FAILURE );
        }

        for ( i = 0; i < NUMLOOPS; ++i ) {

                if ( ( rcvd = splice( in, NULL, filedes[1], NULL, BUFSIZE, SPLICE_F_MORE | SPLICE_F_MOVE ) ) < 0 ) {
                        perror( "splice" );
                        exit( EXIT_FAILURE );
                }

                if ( splice( filedes[0], NULL, out, NULL, rcvd, SPLICE_F_MORE | SPLICE_F_MOVE ) < 0 ) {
                        perror( "splice" );
                        exit( EXIT_FAILURE );
                }
        }
}

The second call to splice in first iteration returns EINVAL ( invalid argument from perror ) everytime - what could be the reason?