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erl_error(3)		      C	Library	Functions		  erl_error(3)

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	corre-
       sponding	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  pro-
	      vided  by	 the caller is printed followed	by a string describing
	      the reason for failure.

       void erl_err_sys(FormatStr, ... )

	      Types:

		 const char *FormatStr;

	      Use this function	after a	failed system call. The	 message  pro-
	      vided  by	 the caller is printed followed	by a string describing
	      the reason 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 re-
       turning 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 examine erl_errno for details.

	      erl_errno	 uses  the  error  codes defined in your system's _er-
	      rno.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 implemented as	a macro	(expanding to,	e.g.,  *_erl_errno()).
	      For reasons of thread- (or task-)safety, this is exactly what we
	      do on most platforms.

Ericsson AB		     erl_interface 3.7.20		  erl_error(3)

NAME | DESCRIPTION | EXPORTS | ERROR REPORTING | EXPORTS

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