Error information from the runtime system, that is, information about a process terminating due to an uncaught error exception, is by default written to terminal (tty):
=ERROR REPORT==== 9-Dec-2003::13:25:02 === Error in process <0.27.0> with exit value: {{badmatch,[1,2,3]},[{m,f,1},{shell,eval_loop,2}]}
The error information is handled by the error logger, a system process registered as error_logger. This process receives all error messages from the Erlang runtime system and also from the standard behaviours and different Erlang/OTP applications.
The exit reasons (such as badarg above) used by the runtime system are described in Errors and Error Handling in the Erlang Reference Manual.
The process error_logger and its user interface (with the same name) are described in error_logger(3). It is possible to configure the system so that error information is written to file instead/as well as tty. Also, it is possible for user defined applications to send and format error information using error_logger.
The standard behaviors (supervisor, gen_server, etc.) sends progress and error information to error_logger. If the SASL application is started, this information is written to tty as well. See SASL Error Logging in the SASL User's Guide for further information.
% erl -boot start_sasl Erlang (BEAM) emulator version 5.4.13 [hipe] [threads:0] [kernel-poll] =PROGRESS REPORT==== 31-Mar-2006::12:45:58 === supervisor: {local,sasl_safe_sup} started: [{pid,<0.33.0>}, {name,alarm_handler}, {mfa,{alarm_handler,start_link,[]}}, {restart_type,permanent}, {shutdown,2000}, {child_type,worker}] =PROGRESS REPORT==== 31-Mar-2006::12:45:58 === supervisor: {local,sasl_safe_sup} started: [{pid,<0.34.0>}, {name,overload}, {mfa,{overload,start_link,[]}}, {restart_type,permanent}, {shutdown,2000}, {child_type,worker}] =PROGRESS REPORT==== 31-Mar-2006::12:45:58 === supervisor: {local,sasl_sup} started: [{pid,<0.32.0>}, {name,sasl_safe_sup}, {mfa,{supervisor, start_link, [{local,sasl_safe_sup},sasl,safe]}}, {restart_type,permanent}, {shutdown,infinity}, {child_type,supervisor}] =PROGRESS REPORT==== 31-Mar-2006::12:45:58 === supervisor: {local,sasl_sup} started: [{pid,<0.35.0>}, {name,release_handler}, {mfa,{release_handler,start_link,[]}}, {restart_type,permanent}, {shutdown,2000}, {child_type,worker}] =PROGRESS REPORT==== 31-Mar-2006::12:45:58 === application: sasl started_at: nonode@nohost Eshell V5.4.13 (abort with ^G) 1>