erl_error(3erl) 						C Library Functions						   erl_error(3erl)

NAME

       erl_error - Error Print Routines

DESCRIPTION

       This module contains some error printing routines taken from Advanced Programming in the UNIX Environment by W. Richard Stevens.

       These  functions are all called in the same manner as printf() , i.e. with a string containing format specifiers followed by a list of cor-
       responding arguments. All output from these functions is to stderr .

EXPORTS

       void erl_err_msg(FormatStr, ... )

	      Types  const char *FormatStr;

	      The message provided by the caller is printed. This function is simply a wrapper for fprintf() .

       void erl_err_quit(FormatStr, ... )

	      Types  const char *FormatStr;

	      Use this function when a fatal error has occurred that is not due to a system call. The message provided by the  caller  is  printed
	      and the process terminates with an exit value of 1. The function does not return.

       void erl_err_ret(FormatStr, ... )

	      Types  const char *FormatStr;

	      Use this function after a failed system call. The message provided by the caller is printed followed by a string describing the rea-
	      son for failure.

       void erl_err_sys(FormatStr, ... )

	      Types  const char *FormatStr;

	      Use this function after a failed system call. The message provided by the caller is printed followed by a string describing the rea-
	      son for failure, and the process terminates with an exit value of 1. The function does not return.

ERROR REPORTING

       Most  functions	in erl_interface report failures to the caller by returning some otherwise meaningless value (typically NULL or a negative
       number). As this only tells you that things did not go well, you will have to examine the error code in erl_errno if you want to  find  out
       more about the failure.

EXPORTS

       volatile int erl_errno

	      erl_errno is initially (at program startup) zero and is then set by many erl_interface functions on failure to a non-zero error code
	      to indicate what kind of error it encountered. A successful function call might change erl_errno (by  calling  some  other  function
	      that  fails),  but  no function will ever set it to zero. This means that you cannot use erl_errno to see if a function call failed.
	      Instead, each function reports failure in its own way (usually by returning a negative number or NULL ), in which case you can exam-
	      ine erl_errno for details.

	      erl_errno uses the error codes defined in your system's <errno.h> .

   Note:
       Actually,  erl_errno  is  a "modifiable lvalue" (just like ISO C defines errno to be) rather than a variable. This means it might be imple-
       mented as a macro (expanding to, e.g., *_erl_errno() ). For reasons of thread- (or task-)safety, this is exactly what we do on  most  plat-
       forms.

Ericsson AB							erl_interface 3.7.3						   erl_error(3erl)