1erl_error(3)                  C Library Functions                 erl_error(3)
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NAME

6       erl_error - Error print routines.
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DESCRIPTION

9       This  module contains some error printing routines taken from "Advanced
10       Programming in the UNIX Environment" by W. Richard Stevens.
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12       These functions are all called in the same manner as printf(), that is,
13       with a string containing format specifiers followed by a list of corre‐
14       sponding arguments. All output from these functions is to stderr.
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EXPORTS

17       void erl_err_msg(FormatStr, ... )
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19              Types:
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21                 const char *FormatStr;
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23              The message provided by the caller is printed. This function  is
24              simply a wrapper for fprintf().
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26       void erl_err_quit(FormatStr, ... )
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28              Types:
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30                 const char *FormatStr;
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32              Use  this  function  when a fatal error has occurred that is not
33              because of a system call. The message provided by the caller  is
34              printed and the process terminates with exit value 1. This func‐
35              tion does not return.
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37       void erl_err_ret(FormatStr, ... )
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39              Types:
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41                 const char *FormatStr;
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43              Use this function after a failed system call. The  message  pro‐
44              vided  by  the caller is printed followed by a string describing
45              the reason for failure.
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47       void erl_err_sys(FormatStr, ... )
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49              Types:
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51                 const char *FormatStr;
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53              Use this function after a failed system call. The  message  pro‐
54              vided  by  the caller is printed followed by a string describing
55              the reason for failure, and the  process  terminates  with  exit
56              value 1. This function does not return.
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ERROR REPORTING

59       Most  functions  in  Erl_Interface  report  failures  to  the caller by
60       returning some otherwise meaningless value (typically NULL or  a  nega‐
61       tive number). As this only tells you that things did not go well, exam‐
62       ine the error code in erl_errno if you want to find out more about  the
63       failure.
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EXPORTS

66       volatile int erl_errno
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68              erl_errno is initially (at program startup) zero and is then set
69              by many Erl_Interface functions on failure to a  non-zero  error
70              code to indicate what kind of error it encountered. A successful
71              function call can change erl_errno (by calling some other  func‐
72              tion  that  fails),  but  no function does never set it to zero.
73              This means that you cannot use erl_errno to see  if  a  function
74              call  failed.  Instead, each function reports failure in its own
75              way (usually by returning a negative number or NULL),  in  which
76              case you can examine erl_errno for details.
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78              erl_errno   uses  the  error  codes  defined  in  your  system's
79              <errno.h>.
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81          Note:
82              erl_errno is a "modifiable lvalue"  (just  like  ISO  C  defines
83              errno to be) rather than a variable. This means it can be imple‐
84              mented as a macro (expanding to,  for  example,  *_erl_errno()).
85              For  reasons  of thread safety (or task safety), this is exactly
86              what we do on most platforms.
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91Ericsson AB                  erl_interface 3.11.3                 erl_error(3)