fix warning+explain

contrib/gmm/gmm_inoutput.h

@@ -362,7 +362,7 @@ namespace gmm {
 				const double exact[], const char* Title,
 				const char* Key, const char* Type,
 				const char* Ptrfmt, const char* Indfmt,
-				char* Valfmt, char* Rhsfmt,
+				const char* Valfmt, const char* Rhsfmt,
 				const char* Rhstype, int shift) {
     /************************************************************************/
     /*  The writeHB function opens the named file and writes the specified  */
@@ -408,7 +408,8 @@ namespace gmm {
     if ( Type[0] != 'P' ) {          /* Skip if pattern only  */
       if ( Valfmt == NULL ) Valfmt = "(4E21.13)";
       ParseRfmt(Valfmt, &Valperline, &Valwidth, &Valprec, &Valflag);
-      if (Valflag == 'D') *strchr(Valfmt,'D') = 'E';
+      //Gmsh fix: this is invalid, as Valfmt is a const char*
+      //if (Valflag == 'D') *strchr(Valfmt,'D') = 'E';
       if (Valflag == 'F')
 	SECURE_SPRINTF2(vformat, sizeof(vformat), "%% %d.%df", Valwidth,
 			Valprec);
@@ -426,7 +427,8 @@ namespace gmm {
 	SECURE_SPRINTF2(rformat,sizeof(rformat), "%% %d.%df",Rhswidth,Rhsprec);
       else
 	SECURE_SPRINTF2(rformat,sizeof(rformat), "%% %d.%dE",Rhswidth,Rhsprec);
-      if (Rhsflag == 'D') *strchr(Rhsfmt,'D') = 'E';
+      //Gmsh fix: this is invalid, as Rhsfmt is a const char*
+      //if (Rhsflag == 'D') *strchr(Rhsfmt,'D') = 'E';
       rhscrd = nrhsentries/Rhsperline;
       if ( nrhsentries%Rhsperline != 0) rhscrd++;
       if ( Rhstype[1] == 'G' ) rhscrd+=rhscrd;