cdef extern from "gsl/gsl_errno.h": ctypedef void gsl_error_handler_t (char * reason, char * file,int line, int gsl_errno) ctypedef void gsl_stream_handler_t (char * label, char * file,int line, char * reason) void gsl_error (char * reason,char * file, int line, int gsl_errno) void gsl_stream_printf (char *label, char *file,int line, char *reason) char * gsl_strerror (int gsl_errno) gsl_error_handler_t * gsl_set_error_handler (gsl_error_handler_t * new_handler) gsl_error_handler_t * gsl_set_error_handler_off() gsl_stream_handler_t * gsl_set_stream_handler (gsl_stream_handler_t * new_handler) FILE * gsl_set_stream (FILE * new_stream)