T2345: Replace instances of NULL with nullptr

The following changes have been applied to src and lib folders:
regex replace: ([^"_])NULL ⇒ \1nullptr (8968 chgs in src, 1153 in lib)
Manually find/change: (void \*) nullptr ⇒ nullptr (1 case)
regex find: ".*?nullptr.*?"
  Manually ~14 cases back to "NULL" in src, ~2 in lib
  regex finds a few false positive where nullptr appears between two
  strings in a function call

lib/message/cslib/src/STUBS_ZMQ/zmq.h

@@ -24,10 +24,10 @@ namespace CSLIB_NS {
 #define ZMQ_REQ 0
 #define ZMQ_REP 0
 
-static void *zmq_ctx_new() {return NULL;}
-static void *zmq_connect(void *, char *) {return NULL;}
+static void *zmq_ctx_new() {return nullptr;}
+static void *zmq_connect(void *, char *) {return nullptr;}
 static int zmq_bind(void *, char *) {return 0;}
-static void *zmq_socket(void *,int) {return NULL;}
+static void *zmq_socket(void *,int) {return nullptr;}
 static void zmq_close(void *) {}
 static void zmq_ctx_destroy(void *) {}
 static void zmq_send(void *, void *, int, int) {}

lib/message/cslib/src/cslib.cpp

@@ -57,7 +57,7 @@ CSlib::CSlib(int csflag, const char *mode, const void *ptr, const void *pcomm)
   else if (csflag == 1) server = 1;
   else error_all("constructor(): Invalid client/server arg");
 
-  if (pcomm == NULL) {
+  if (pcomm == nullptr) {
     me = 0;
     nprocs = 1;
 
@@ -82,19 +82,19 @@ CSlib::CSlib(int csflag, const char *mode, const void *ptr, const void *pcomm)
   }
 
   maxfield = 0;
-  fieldID = fieldtype = fieldlen = fieldoffset = NULL;
+  fieldID = fieldtype = fieldlen = fieldoffset = nullptr;
   maxheader = 0;
-  header = NULL;
+  header = nullptr;
   maxbuf = 0;
-  buf = NULL;
+  buf = nullptr;
 
-  recvcounts = displs = NULL;
+  recvcounts = displs = nullptr;
   maxglobal = 0;
-  allids = NULL;
+  allids = nullptr;
   maxfieldbytes = 0;
-  fielddata = NULL;
+  fielddata = nullptr;
   
-  pad = "\0\0\0\0\0\0\0";    // just length 7 since will have trailing NULL
+  pad = "\0\0\0\0\0\0\0";    // just length 7 since will have trailing nullptr
   
   nsend = nrecv = 0;
 }
@@ -218,7 +218,7 @@ void CSlib::pack_parallel(int id, int ftype,
   // nlocal datums, each of nper length, from all procs
   // final data in buf = datums for all natoms, ordered by ids
 
-  if (recvcounts == NULL) {
+  if (recvcounts == nullptr) {
     recvcounts = (int *) smalloc(nprocs*sizeof(int));
     displs = (int *) smalloc(nprocs*sizeof(int));
   }
@@ -706,9 +706,9 @@ void CSlib::deallocate_fields()
 
 void *CSlib::smalloc(int nbytes)
 {
-  if (nbytes == 0) return NULL;
+  if (nbytes == 0) return nullptr;
   void *ptr = malloc(nbytes);
-  if (ptr == NULL) {
+  if (ptr == nullptr) {
     char str[128];
     sprintf(str,"malloc(): Failed to allocate %d bytes",nbytes);
     error_one(str);
@@ -722,11 +722,11 @@ void *CSlib::srealloc(void *ptr, int nbytes)
 {
   if (nbytes == 0) {
     sfree(ptr);
-    return NULL;
+    return nullptr;
   }
   
   ptr = realloc(ptr,nbytes);
-  if (ptr == NULL) {
+  if (ptr == nullptr) {
     char str[128];
     sprintf(str,"realloc(): Failed to reallocate %d bytes",nbytes);
     error_one(str);
@@ -738,7 +738,7 @@ void *CSlib::srealloc(void *ptr, int nbytes)
 
 void CSlib::sfree(void *ptr)
 {
-  if (ptr == NULL) return;
+  if (ptr == nullptr) return;
   free(ptr);
 }
 

lib/message/cslib/src/cslib_wrap.cpp

@@ -44,7 +44,7 @@ void cslib_open_fortran(int csflag, const char *mode, const char *str,
                         const void *pcomm, void **csptr)
 {
   MPI_Comm ccomm;
-  void *pccomm = NULL;
+  void *pccomm = nullptr;
 
   if (pcomm) {
     MPI_Fint *fcomm = (MPI_Fint *) pcomm;

lib/message/cslib/src/msg.cpp

@@ -80,9 +80,9 @@ void Msg::allocate(int nheader, int &maxheader, int *&header,
 
 void *Msg::smalloc(int nbytes)
 {
-  if (nbytes == 0) return NULL;
+  if (nbytes == 0) return nullptr;
   void *ptr = (void *) malloc(nbytes);
-  if (ptr == NULL) {
+  if (ptr == nullptr) {
     char str[128];
     sprintf(str,"Failed to allocate %d bytes",nbytes);
   }
@@ -93,7 +93,7 @@ void *Msg::smalloc(int nbytes)
 
 void Msg::sfree(void *ptr)
 {
-  if (ptr == NULL) return;
+  if (ptr == nullptr) return;
   free(ptr);
 }
 

lib/message/cslib/src/msg_mpi_two.cpp

@@ -52,7 +52,7 @@ void MsgMPITwo::init(char *filename)
 {
   if (client) {
     if (me == 0) {
-      FILE *fp = NULL;
+      FILE *fp = nullptr;
       while (!fp) {
         fp = fopen(filename,"r");
         if (!fp) sleep(1);

lib/message/cslib/src/msg_zmq.cpp

@@ -99,12 +99,12 @@ void MsgZMQ::send(int nheader, int *header, int nbuf, char *buf)
 
   if (me == 0) {
     zmq_send(socket,lengths,2*sizeof(int),0);
-    zmq_recv(socket,NULL,0,0);
+    zmq_recv(socket,nullptr,0,0);
   }
 
   if (me == 0) {
     zmq_send(socket,header,nheader*sizeof(int),0);
-    zmq_recv(socket,NULL,0,0);
+    zmq_recv(socket,nullptr,0,0);
   }
 
   if (me == 0) zmq_send(socket,buf,nbuf,0);
@@ -125,7 +125,7 @@ void MsgZMQ::recv(int &maxheader, int *&header, int &maxbuf, char *&buf)
 {
   if (me == 0) {
     zmq_recv(socket,lengths,2*sizeof(int),0);
-    zmq_send(socket,NULL,0,0);
+    zmq_send(socket,nullptr,0,0);
   }
   if (nprocs > 1) MPI_Bcast(lengths,2,MPI_INT,0,world);
 
@@ -135,7 +135,7 @@ void MsgZMQ::recv(int &maxheader, int *&header, int &maxbuf, char *&buf)
 
   if (me == 0) {
     zmq_recv(socket,header,nheader*sizeof(int),0);
-    zmq_send(socket,NULL,0,0);
+    zmq_send(socket,nullptr,0,0);
   }
   if (nprocs > 1) MPI_Bcast(header,nheader,MPI_INT,0,world);