isDigit -> ISDIGIT (simplification, backported from 8.7/9.0)

generic/tclStubLib.c

@@ -4,7 +4,7 @@
  *	Stub object that will be statically linked into extensions that want
  *	to access Tcl.
  *
- * Copyright (c) 1998-1999 by Scriptics Corporation.
+ * Copyright (c) 1998-1999 Scriptics Corporation.
  * Copyright (c) 1998 Paul Duffin.
  *
  * See the file "license.terms" for information on usage and redistribution of
@@ -24,13 +24,10 @@ const TclIntStubs *tclIntStubsPtr = NULL;
 const TclIntPlatStubs *tclIntPlatStubsPtr = NULL;
 
 /*
- * Use our own isDigit to avoid linking to libc on windows
+ * Use our own ISDIGIT to avoid linking to libc on windows
  */
 
-static int isDigit(const int c)
-{
-    return (c >= '0' && c <= '9');
-}
+#define ISDIGIT(c) (((unsigned)((c)-'0')) <= 9)
 
 /*
  *----------------------------------------------------------------------
@@ -56,9 +53,9 @@ Tcl_InitStubs(
     const char *version,
     int exact)
 {
-    Interp *iPtr = (Interp *) interp;
+    Interp *iPtr = (Interp *)interp;
     const char *actualVersion = NULL;
-    ClientData pkgData = NULL;
+    void *pkgData = NULL;
     const TclStubs *stubsPtr = iPtr->stubTable;
 
     /*
@@ -82,7 +79,7 @@ Tcl_InitStubs(
 	int count = 0;
 
 	while (*p) {
-	    count += !isDigit(*p++);
+	    count += !ISDIGIT(*p++);
 	}
 	if (count == 1) {
 	    const char *q = actualVersion;
@@ -91,7 +88,7 @@ Tcl_InitStubs(
 	    while (*p && (*p == *q)) {
 		p++; q++;
 	    }
-	    if (*p || isDigit(*q)) {
+	    if (*p || ISDIGIT(*q)) {
 		/* Construct error message */
 		stubsPtr->tcl_PkgRequireEx(interp, "Tcl", version, 1, NULL);
 		return NULL;