88 lines
2.3 KiB
Groff
88 lines
2.3 KiB
Groff
.\" Copyright (c) 1988 Massachusetts Institute of Technology,
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.\" Student Information Processing Board.
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.\"
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.TH COM_ERR 3 "22 Nov 1988" SIPB
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.SH NAME
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com_err \- common error display routine
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.SH SYNOPSIS
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.nf
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#include <et/com_err.h>
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void (*\fIproc\fR) (const char *, long, const char *, va_list);
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.PP
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void com_err (const char *whoami, long code, const char *format, ...);
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.PP
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proc = set_com_err_hook (proc);
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.PP
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proc = reset_com_err_hook ();
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.PP
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void initialize_XXXX_error_table ();
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.fi
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.SH DESCRIPTION
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.I Com_err
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displays an error message on the standard error stream
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.I stderr
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(see
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.IR stdio (3S))
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composed of the
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.I whoami
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string, which should specify the program name or some subportion of
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a program, followed by an error message generated from the
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.I code
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value (derived from
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.IR compile_et (1)),
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and a string produced using the
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.I format
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string and any following arguments, in the same style as
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.IR fprintf (3).
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The behavior of
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.I com_err
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can be modified using
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.I set_com_err_hook;
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this defines a procedure which is called with the arguments passed to
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.I com_err,
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instead of the default internal procedure which sends the formatted
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text to error output. Thus the error messages from a program can all
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easily be diverted to another form of diagnostic logging, such as
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.IR syslog (3).
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.I Reset_com_err_hook
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may be used to restore the behavior of
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.I com_err
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to its default form. Both procedures return the previous ``hook''
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value. These ``hook'' procedures must have the declaration given for
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.I proc
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above in the synopsis.
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The
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.I initialize_XXXX_error_table
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routine is generated mechanically by
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.IR compile_et (1)
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from a source file containing names and associated strings. Each
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table has a name of up to four characters, which is used in place of
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the
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.B XXXX
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in the name of the routine. These routines should be called before
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any of the corresponding error codes are used, so that the
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.I com_err
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library will recognize error codes from these tables when they are
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used.
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The
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.B com_err.h
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header file should be included in any source file that uses routines
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from the
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.I com_err
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library; executable files must be linked using
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.I ``-lcom_err''
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in order to cause the
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.I com_err
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library to be included.
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.\" .IR for manual entries
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.\" .PP for paragraph breaks
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.SH "SEE ALSO"
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compile_et (1), syslog (3).
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Ken Raeburn, "A Common Error Description Library for UNIX".
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