mirror of
https://github.com/lcn2/calc.git
synced 2025-08-19 01:13:27 +03:00
80 lines
2.5 KiB
Plaintext
80 lines
2.5 KiB
Plaintext
NAME
|
|
errno - return or set a stored error-number
|
|
|
|
SYNOPSIS
|
|
errno([errnum])
|
|
|
|
TYPES
|
|
errnum integer, 0 <= errnum <= 32767
|
|
|
|
return integer
|
|
|
|
DESCRIPTION
|
|
|
|
Whenever an operation or evaluation of function returns an error-value,
|
|
the numerical code for that value is stored as calc_errno.
|
|
|
|
errno() returns the current value of calc_errno.
|
|
|
|
errno(errnum) sets calc_errno to the value errnum and returns its
|
|
previous value.
|
|
|
|
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"
|
|
|
|
; errno(0)
|
|
0
|
|
; errmax(errcount()+4)
|
|
20
|
|
; badfile = fopen("not_a_file", "r")
|
|
; print errno(), error(), strerror()
|
|
2 System error 2 No such file or directory
|
|
|
|
; a = 1/0
|
|
; print errno(), error(), strerror()
|
|
10001 Error 10001 Division by zero
|
|
|
|
LIMITS
|
|
none
|
|
|
|
LINK LIBRARY
|
|
none
|
|
|
|
SEE ALSO
|
|
errmax, errcount, error, strerror, iserror, newerror, errorcodes,
|
|
stoponerror
|
|
|
|
## Copyright (C) 1999-2006,2021 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/
|