Files
calc/help/errno
Landon Curt Noll 40c8f875c1 rename E__COUNT to ECOUNT
Rename the #define E__COUNT to ECOUNT to avoid confusion
with "E_STRING" error symbols.

Improve formatting of help/error, help/errno, and help/strerror.

Update .gitignore.
2023-09-13 20:20:46 -07:00

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NAME
errno - return or set a the global calc_errno value
SYNOPSIS
errno([errnum | "E_STRING"])
TYPES
errnum integer
E_STRING string
return integer
DESCRIPTION
With errno(errnum) numeric argument:
errno(errnum) sets "global calc_errno value" to the value
errnum and returns its previous value. Unlike error(errnum)
calling errno(errnum) does NOT increment the global calc
error count (see help errcount).
With errno("E_STRING") string argument:
XXX - fill in - XXX
With errno() no argument:
errno() returns the current value of "global calc_errno
value". Unlike error() calling errno() does NOT increment
the global calc error count (see help errcount).
NOTE:
The errno() builtin should not be confused with the errno
used by libc in C. The range of errnum extend beyond the
C's libc errno. See help error for information on the mean
of various errnum ranges.
Unlike error() calling errno() does NOT increment the global
calc error count (see help errcount).
Whenever an operation or evaluation of function returns an error-value,
the numerical code for that value is stored as "global calc_errno value".
The term "global calc_errno value" is an internal calc state.
This is NOT a calc variable called calc_errno.
To detect whether an error occurs during some sequence of operations,
one may immediately before that sequence set the stored error-number
to zero by errno(0), and then after the operations, whether or not
an error has occurred will be indicated by errno() being nonzero or
zero. If a non-zero value is returned, that value will be the code
for the most recent error encountered.
The default argument for the functions error() and strerror() is the
currently stored error-number; in particular, if no error-value has
been returned after the last errno(0), strerror() will return
"No error".
EXAMPLE
; ## Assuming there is no file with name "not_a_file"
; errcount(0),; errmax(20),;
; print errcount(), errmax()
0 20
; badfile = fopen("not_a_file", "r")
; print errcount(), errno(), strerror()
1 2 No such file or directory
; a = 1/0
; print errcount(), errno(), strerror()
2 10001 Division by zero
LIMITS
0 <= errnum <= 32767
E_STRING is string matching the regular expression: "^E_[A-Z0-9_]+$"
LINK LIBRARY
int calc_errno; /* global calc_errno value */
CONST struct errtbl error_table[ECOUNT+2]; /* calc error codes, error symbols and error messages */
SEE ALSO
errmax, errcount, error, strerror, iserror, newerror, errorcodes,
stoponerror
## Copyright (C) 1999-2006,2021,2023 Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL. You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
##
## Under source code control: 1994/10/27 03:05:08
## File existed as early as: 1994
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/