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Provide an environment variabloe, EXPR_COMPAT, which disables option

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parsing for compatibility with old implementations.
This commit is contained in:
wollman 2002-04-22 21:23:09 +00:00
parent 3f7a25452f
commit d4058a4eaf
2 changed files with 27 additions and 10 deletions
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18
bin/expr/expr.1
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@ -111,7 +111,9 @@ otherwise 0.
.Pp
Parentheses are used for grouping in the usual manner.
.Pp
This version of
Unless the
.Ev EXPR_COMPAT
variable is defined in the process environment, this version of
.Nm
adheres to the
.Tn POSIX
@ -141,6 +143,15 @@ The syntax of the
command in general is historic and inconvenient.
New applications are advised to use shell arithmetic rather than
.Nm .
.Sh ENVIRONMENT
.Bl -tag -compact -width EXPR_COMPAT
.It Ev EXPR_COMPAT
If set,
.Nm
will emulate historic
.Nm
implementations which did not obey the Utility Syntax Guidelines.
.El
.Sh EXAMPLES
.Bl -bullet
.It
@ -216,7 +227,10 @@ the expression is invalid.
The
.Nm
utility conforms to
.St -p1003.1-2001 .
.St -p1003.1-2001 ,
provided that the
.Ev EXPR_COMPAT
environment variable is not defined.
.Tn POSIX
does not specify whether arithmetic overflow is detected, nor does it specify
the possible range of integer arguments to

19
bin/expr/expr.y
View File

@ -270,14 +270,17 @@ main(int argc, char *argv[])
int c;
setlocale (LC_ALL, "");
while ((c = getopt(argc, argv, "")) != -1)
switch (c) {
default:
fprintf(stderr, "usage: expr [--] expression\n");
exit(ERR_EXIT);
}
av = argv + optind;
if (getenv("EXPR_COMPAT") != NULL) {
av = argv + 1;
} else {
while ((c = getopt(argc, argv, "")) != -1)
switch (c) {
default:
fprintf(stderr,"usage: expr [--] expression\n");
exit(ERR_EXIT);
}
av = argv + optind;
}
yyparse();