diff --git a/regtest/basic/rt-make-exceptions/main.cpp b/regtest/basic/rt-make-exceptions/main.cpp
index baae4ae446..9d42429286 100644
--- a/regtest/basic/rt-make-exceptions/main.cpp
+++ b/regtest/basic/rt-make-exceptions/main.cpp
@@ -58,7 +58,7 @@ int main(){
   int natoms=10;
 
   std::vector<double> positions(3*natoms,0.0);
-  for(unsigned i=0;i<3*natoms;i++) positions[i]=i;
+  for(int i=0;i<3*natoms;i++) positions[i]=i;
   std::vector<double> masses(natoms,1.0);
   std::vector<double> forces(3*natoms,0.0);
   std::vector<double> box(9,0.0);
@@ -145,7 +145,7 @@ int main(){
     plumed.cmd("setVirial",&virial[0]);
     plumed.cmd("setMasses",&masses[0]);
 // set positions after having passed the pointer. They should be accessed here (at "calc").
-    for(unsigned i=0;i<3*natoms;i++) positions[i]=i*step;
+    for(int i=0;i<3*natoms;i++) positions[i]=i*step;
     plumed.cmd("calc");
 
 // this should fail
diff --git a/src/wrapper/Plumed.h b/src/wrapper/Plumed.h
index 3ea2bc9c75..5094a301ad 100644
--- a/src/wrapper/Plumed.h
+++ b/src/wrapper/Plumed.h
@@ -2346,7 +2346,7 @@ class Plumed {
     char msg[__PLUMED_WRAPPER_CXX_EXCEPTION_BUFFER];
     void init(const char* msg) __PLUMED_WRAPPER_CXX_NOEXCEPT {
       this->msg[0]='\0';
-      __PLUMED_WRAPPER_STD strncat(this->msg,msg,__PLUMED_WRAPPER_CXX_EXCEPTION_BUFFER-1);
+      __PLUMED_WRAPPER_STD strncpy(this->msg,msg,__PLUMED_WRAPPER_CXX_EXCEPTION_BUFFER);
       this->msg[__PLUMED_WRAPPER_CXX_EXCEPTION_BUFFER-1]='\0';
       if(PlumedGetenvExceptionsDebug() && __PLUMED_WRAPPER_STD strlen(msg) > __PLUMED_WRAPPER_CXX_EXCEPTION_BUFFER-1) __PLUMED_WRAPPER_STD fprintf(stderr,"+++ WARNING: message will be truncated\n");
     }
@@ -3831,7 +3831,7 @@ void* plumed_attempt_dlopen(const char*path,int mode) {
       __PLUMED_FPRINTF(stderr,"+++ Allocation error +++\n");
       __PLUMED_WRAPPER_STD abort();
     }
-    __PLUMED_WRAPPER_STD strncpy(pathcopy,path,strlenpath+1);
+    __PLUMED_WRAPPER_STD memcpy(pathcopy,path,strlenpath+1);
     pc=pathcopy+strlenpath-6;
     while(pc>=pathcopy && __PLUMED_WRAPPER_STD memcmp(pc,"Kernel",6)) pc--;
     if(pc>=pathcopy) {