👤
Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:
Select Section of Man Page:
Select Man Page Repository:

NetBSD 6.1.5 - man page for reset_com_err_hook (netbsd section 3)

COM_ERR(3)			   BSD Library Functions Manual 		       COM_ERR(3)

NAME
     com_err, com_err_va, error_message, error_table_name, init_error_table, set_com_err_hook,
     reset_com_err_hook, add_to_error_table, initialize_error_table_r free_error_table, com_right
     -- common error display library

LIBRARY
     Common Error Library (libcom_err, -lcom_err)

SYNOPSIS
     #include <stdio.h>
     #include <stdarg.h>
     #include <krb5/com_err.h>
     #include "XXX_err.h"

     typedef void (*errf)(const char *, long, const char *, ...);

     void
     com_err(const char *whoami, long code, const char *format, ...);

     void
     com_err_va(const char *whoami, long code, const char *format, ...);

     const char *
     error_message(long code);

     const char *
     error_table_name(int num);

     int
     init_error_table(const char **msgs, long base, int count);

     errf
     set_com_err_hook(errf func);

     errf
     reset_com_err_hook();

     void
     add_to_error_table(struct et_list *new_table);

     void
     initialize_error_table_r(struct et_list **et_list, const char **msgs, int base, long count);

     void
     free_error_table(struct et_list *);

     const char *
     com_right(struct et_list *list, long, code");

DESCRIPTION
     The com_err library provides a common error-reporting mechanism for defining and accessing
     error codes and descriptions for application software packages.  Error descriptions are
     defined in a table and error codes are used to index the table.  The error table, the
     descriptions and the error codes are generated using compile_et(1).

     The error table is registered with the com_err library by calling its initialisation func-
     tion defined in its header file.  The initialisation function is generally defined as
     initialize_<name>_error_table(), where name is the name of the error table.

     If a thread-safe version of the library is needed initialize_<name>_error_table_r() that
     internally calls initialize_error_table_r() instead be used.

     Any variable which is to contain an error code should be declared <name>_error_number where
     name is the name of the error table.

FUNCTIONS
     The following functions are available to the application developer:

     com_err(whoami, code, format, ...)
	      Displays an error message on standard error composed of the whoami string, which
	      should specify the program name, followed by an error message generated from code,
	      and a string produced using the printf(3) format string and any following argu-
	      ments.  If format is NULL, the formatted message will not be printed.  The argument
	      format may not be omitted.

     com_err_va(whoami, code, format, va_list args)
	      This routine provides an interface, equivalent to com_err(), which may be used by
	      higher-level variadic functions (functions which accept variable numbers of argu-
	      ments).

     error_message(code)
	      Returns the character string error message associate with code.  If code is
	      associated with an unknown error table, or if code is associated with a known error
	      table but is not in the table, a string of the form `Unknown code XXXX NN' is
	      returned, where XXXX is the error table name produced by reversing the compaction
	      performed on the error table number implied by that error code, and NN is the off-
	      set from that base value.

	      Although this routine is available for use when needed, its use should be left to
	      circumstances which render com_err() unusable.

	      com_right() returns the error string just like com_err but in a thread-safe way.

     error_table_name(num)
	      Convert a machine-independent error table number num into an error table name.

     init_error_table(msgs, base, count)
	      Initialise the internal error table with the array of character string error mes-
	      sages in msgs of length count.  The error codes are assigned incrementally from
	      base.  This function is useful for using the error-reporting mechanism with custom
	      error tables that have not been generated with compile_et(1).  Although this rou-
	      tine is available for use when needed, its use should be restricted.

	      initialize_error_table_r() initialize the et_list in the same way as
	      init_error_table(), but in a thread-safe way.

     set_com_err_hook(func)
	      Provides a hook into the com_err library to allow the routine func to be dynami-
	      cally substituted for com_err().	After set_com_err_hook()
	       has been called, calls to com_err() will turn into calls to the new hook routine.
	      This function is intended to be used in daemons to use a routine which calls
	      syslog(3), or in a window system application to pop up a dialogue box.

     reset_com_err_hook()
	      Turns off the hook set in set_com_err_hook().

     add_to_error_table(new_table)
	      Add the error table, its messages strings and error codes in new_table to the
	      internal error table.

EXAMPLES
     The following is an example using the table defined in compile_et(1):

	     #include <stdio.h>
	     #include <stdarg.h>
	     #include <syslog.h>

	     #include "test_err.h"

	     void
	     hook(const char *whoami, long code,
		     const char *format, va_list args)
	     {
		     char buffer[BUFSIZ];
		     static int initialized = 0;

		     if (!initialized) {
			     openlog(whoami, LOG_NOWAIT, LOG_DAEMON);
			     initialized = 1;
		     }
		     vsprintf(buffer, format, args);
		     syslog(LOG_ERR, "%s %s", error_message(code), buffer);
	     }

	     int
	     main(int argc, char *argv[])
	     {
		     char *whoami = argv[0];

		     initialize_test_error_table();
		     com_err(whoami, TEST_INVAL, "before hook");
		     set_com_err_hook(hook);
		     com_err(whoami, TEST_IO, "after hook");
		     return (0);
	     }

SEE ALSO
     compile_et(1)

BSD					   July 7, 2005 				      BSD


All times are GMT -4. The time now is 09:58 AM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
×
UNIX.COM Login
Username:
Password:  
Show Password