From 86d4ec7a45698e4168318f821894a95cfbfa216d Mon Sep 17 00:00:00 2001
From: Richard Berger <richard.berger@temple.edu>
Date: Fri, 7 May 2021 19:53:18 -0400
Subject: [PATCH] Replace localtime() with thread-safe fmt::localtime()

---
 src/bond.cpp     | 10 +++++-----
 src/dump_dcd.cpp | 12 +++++++-----
 src/pair.cpp     | 12 ++++++------
 3 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/src/bond.cpp b/src/bond.cpp
index 049d5da823..22a7b27eda 100644
--- a/src/bond.cpp
+++ b/src/bond.cpp
@@ -22,6 +22,7 @@
 #include "neighbor.h"
 #include "suffix.h"
 #include "update.h"
+#include "fmt/chrono.h"
 
 #include <ctime>
 
@@ -283,14 +284,13 @@ void Bond::write_file(int narg, char **arg)
                      "DATE: {}\n", table_file, date);
       fp = fopen(table_file.c_str(),"a");
     } else {
-      char datebuf[16];
       time_t tv = time(nullptr);
-      strftime(datebuf,15,"%Y-%m-%d",localtime(&tv));
+      std::tm current_date = fmt::localtime(tv);
       utils::logmesg(lmp,"Creating table file {} with "
-                     "DATE: {}\n", table_file, datebuf);
+                     "DATE: {:%Y-%m-%d}\n", table_file, current_date);
       fp = fopen(table_file.c_str(),"w");
-      if (fp) fmt::print(fp,"# DATE: {} UNITS: {} Created by bond_write\n",
-                         datebuf, update->unit_style);
+      if (fp) fmt::print(fp,"# DATE: {:%Y-%m-%d} UNITS: {} Created by bond_write\n",
+                         current_date, update->unit_style);
     }
     if (fp == nullptr)
       error->one(FLERR,"Cannot open bond_write file {}: {}",
diff --git a/src/dump_dcd.cpp b/src/dump_dcd.cpp
index 3bbf929845..0b02f1f1f6 100644
--- a/src/dump_dcd.cpp
+++ b/src/dump_dcd.cpp
@@ -27,6 +27,7 @@
 #include "group.h"
 #include "memory.h"
 #include "error.h"
+#include "fmt/chrono.h"
 
 using namespace LAMMPS_NS;
 
@@ -309,8 +310,8 @@ void DumpDCD::write_dcd_header(const char *remarks)
   uint32_t out_integer;
   float out_float;
   char title_string[200];
-  time_t cur_time;
-  struct tm *tmbuf;
+  time_t t;
+  std::tm current_time;
 
   int ntimestep = update->ntimestep;
 
@@ -345,10 +346,11 @@ void DumpDCD::write_dcd_header(const char *remarks)
   strncpy(title_string,remarks,80);
   title_string[79] = '\0';
   fwrite(title_string,80,1,fp);
-  cur_time=time(nullptr);
-  tmbuf=localtime(&cur_time);
+  t = time(nullptr);
+  current_time = fmt::localtime(t);
+  std::string s = fmt::format("REMARKS Created {:%d %B,%Y at %H:%M}", current_time);
   memset(title_string,' ',81);
-  strftime(title_string,80,"REMARKS Created %d %B,%Y at %H:%M",tmbuf);
+  strncpy(title_string, s.c_str(), 80);
   fwrite(title_string,80,1,fp);
   fwrite_int32(fp,164);
   fwrite_int32(fp,4);
diff --git a/src/pair.cpp b/src/pair.cpp
index 42ec13374b..7f41114fc0 100644
--- a/src/pair.cpp
+++ b/src/pair.cpp
@@ -30,6 +30,7 @@
 #include "neighbor.h"
 #include "suffix.h"
 #include "update.h"
+#include "fmt/chrono.h"
 
 #include <cfloat>    // IWYU pragma: keep
 #include <climits>   // IWYU pragma: keep
@@ -1738,14 +1739,13 @@ void Pair::write_file(int narg, char **arg)
                      table_file, date);
       fp = fopen(table_file.c_str(),"a");
     } else {
-      char datebuf[16];
       time_t tv = time(nullptr);
-      strftime(datebuf,15,"%Y-%m-%d",localtime(&tv));
-      utils::logmesg(lmp,"Creating table file {} with DATE: {}\n",
-                     table_file, datebuf);
+      std::tm current_date = fmt::localtime(tv);
+      utils::logmesg(lmp,"Creating table file {} with DATE: {:%Y-%m-%d}\n",
+                     table_file, current_date);
       fp = fopen(table_file.c_str(),"w");
-      if (fp) fmt::print(fp,"# DATE: {} UNITS: {} Created by pair_write\n",
-                         datebuf, update->unit_style);
+      if (fp) fmt::print(fp,"# DATE: {:%Y-%m-%d} UNITS: {} Created by pair_write\n",
+                         current_date, update->unit_style);
     }
     if (fp == nullptr)
       error->one(FLERR,"Cannot open pair_write file {}: {}",