diff options
| -rw-r--r-- | txr.1 | 29 | ||||
| -rw-r--r-- | unwind.c | 50 |
2 files changed, 43 insertions, 36 deletions
@@ -28237,14 +28237,17 @@ macro. If no catch or accepting handler is found, control is transferred to the function stored in the .code *unhandled-hook* -variable. If that function returns, the process terminates. +variable. If that function returns, then unwinding is performed +after which the process terminates (unless the unwinding actions +intercept the control to prevent that). .IP - If no catch or accepting handler is found and .code *unhandled-hook* is .codn nil , then a built-in strategy for handling the exception is invoked, -consisting of printing some informational messages and terminating. +consisting of unwinding, and then printing some informational messages and +terminating. .PP From the above it should be evident that there are two ways by which exceptions @@ -28674,25 +28677,25 @@ with the following arguments: the exception type symbol, the exception object, and a third value which is either .code nil or else the form which was being evaluated when the exception was thrown. +The call occurs before any unwinding takes place. -Otherwise, if the variable is +If the variable is +.codn nil , +or isn't a function, or the function returns after being called, +then unwinding takes place, after which some informational messages are printed +about the exception, and the process exits with a failed termination status. + +In the case when the variable contains a object other than .code nil -some informational messages are printed about the exception, and the process -exits with a failed termination status. -In the same situation, if the variable contains an object which is not a -function, the process terminates abnormally as if by a call to the -.code abort -function. +which isn't a function, a diagnostic message is printed on the +.code *stderr* +stream prior to unwinding. Prior to the function being called, the .code *unhandled-hook* variable is reset to .codn nil . -If the function registered in -.code *unhandled-hook* -returns, the process exits with a failed termination status. - Note: the functions .code source-loc or @@ -48,6 +48,7 @@ static uw_frame_t *uw_stack; static uw_frame_t *uw_env_stack; static uw_frame_t *uw_exit_point; static uw_frame_t toplevel_env; +static uw_frame_t unhandled_ex; static val unhandled_hook_s, types_s, jump_s, sys_cont_s, sys_cont_poison_s; static val sys_cont_free_s, sys_capture_cont_s; @@ -94,11 +95,32 @@ static void uw_unwind_to_exit_point(void) } } - if (!uw_stack) - abort(); + if (uw_exit_point == &unhandled_ex) { + val sym = unhandled_ex.ca.sym; + val args = unhandled_ex.ca.args; + + if (opt_loglevel >= 1) { + val prefix = format(nil, lit("~a:"), prog_string, nao); + + format(std_error, lit("~a unhandled exception of type ~a:\n"), + prefix, sym, nao); + + error_trace(sym, args, std_error, prefix); + } + if (uw_exception_subtype_p(sym, query_error_s) || + uw_exception_subtype_p(sym, file_error_s)) { + if (opt_print_bindings) + put_line(lit("false"), std_output); + } + + exit(EXIT_FAILURE); + } uw_exit_point = 0; + if (!uw_stack) + abort(); + switch (uw_stack->uw.type) { case UW_BLOCK: extended_longjmp(uw_stack->bl.jb, 1); @@ -517,33 +539,15 @@ val uw_throw(val sym, val args) set(pfun, nil); if (fun) { - if (functionp(fun)) { + if (functionp(fun)) funcall3(fun, sym, args, last_form_evaled); - } else { + else format(std_error, lit("~a: *unhandled-hook* ~s isn't a function\n"), prog_string, fun, nao); - abort(); - } - - exit(EXIT_FAILURE); } } - if (opt_loglevel >= 1) { - val prefix = format(nil, lit("~a:"), prog_string, nao); - - format(std_error, lit("~a unhandled exception of type ~a:\n"), - prefix, sym, nao); - - error_trace(sym, args, std_error, prefix); - } - if (uw_exception_subtype_p(sym, query_error_s) || - uw_exception_subtype_p(sym, file_error_s)) { - if (opt_print_bindings) - put_line(lit("false"), std_output); - } - - exit(EXIT_FAILURE); + ex = &unhandled_ex; } ex->ca.sym = sym; |