dselect: Use C++11 nullptr instead of 0 or NULL

It is way more descriptive, and has a better type. Check for C++11
compiler support and fallback nullptr to 0 if unavailable.

1 files changed, 12 insertions, 9 deletions

diff --git a/dselect/methparse.cc b/dselect/methparse.cc
index 0902b441a..2beb8ca2e 100644
--- a/dselect/methparse.cc
+++ b/dselect/methparse.cc
@@ -44,8 +44,8 @@
 #include "method.h"
 
 int noptions=0;
-struct dselect_option *options=0, *coption=0;
-struct method *methods=0;
+struct dselect_option *options = nullptr, *coption = nullptr;
+struct method *methods = nullptr;
 
 static void DPKG_ATTR_NORET
 badmethod(const char *pathname, const char *why)
@@ -62,7 +62,10 @@ eofmethod(const char *pathname, FILE *f, const char *why)
 
 void readmethods(const char *pathbase, dselect_option **optionspp, int *nread) {
   static const char *const methodprograms[]= {
-    METHODSETUPSCRIPT, METHODUPDATESCRIPT, METHODINSTALLSCRIPT, 0
+    METHODSETUPSCRIPT,
+    METHODUPDATESCRIPT,
+    METHODINSTALLSCRIPT,
+    nullptr
   };
   const char *const *ccpp;
   int methodlen, c, baselen;
@@ -92,7 +95,7 @@ void readmethods(const char *pathbase, dselect_option **optionspp, int *nread) {
 
   debug(dbg_general, "readmethods('%s',...) directory open", pathbase);
 
-  while ((dent= readdir(dir)) != 0) {
+  while ((dent = readdir(dir)) != nullptr) {
     c= dent->d_name[0];
     debug(dbg_general, "readmethods('%s',...) considering '%s' ...",
           pathbase, dent->d_name);
@@ -130,7 +133,7 @@ void readmethods(const char *pathbase, dselect_option **optionspp, int *nread) {
     strcpy(meth->path+baselen+1+methodlen,"/");
     meth->pathinmeth= meth->path+baselen+1+methodlen+1;
     meth->next= methods;
-    meth->prev = 0;
+    meth->prev = nullptr;
     if (methods)
       methods->prev = meth;
     methods= meth;
@@ -188,7 +191,7 @@ void readmethods(const char *pathbase, dselect_option **optionspp, int *nread) {
       if (!descfile) {
         if (errno != ENOENT)
           ohshite(_("unable to open option description file `%.250s'"),pathbuf);
-        opt->description= 0;
+        opt->description = nullptr;
       } else { /* descfile != 0 */
         if (fstat(fileno(descfile),&stab))
           ohshite(_("unable to stat option description file `%.250s'"),pathbuf);
@@ -229,7 +232,7 @@ void readmethods(const char *pathbase, dselect_option **optionspp, int *nread) {
   delete[] pathbuf;
 }
 
-static char *methoptfile= 0;
+static char *methoptfile = nullptr;
 
 void getcurrentopt() {
   char methoptbuf[IMETHODMAXLEN+1+IOPTIONMAXLEN+2];
@@ -237,10 +240,10 @@ void getcurrentopt() {
   int l;
   char *p;
 
-  if (methoptfile == NULL)
+  if (methoptfile == nullptr)
     methoptfile = dpkg_db_get_path(CMETHOPTFILE);
 
-  coption= 0;
+  coption = nullptr;
   cmo= fopen(methoptfile,"r");
   if (!cmo) {
     if (errno == ENOENT) return;