https://community.intel.com/t5/Software-Archive/Lost-Memory/m-p/988220#M27681 Yes, that could cause various nasty behaviours. I feel inclined to write a debugging anecdote of mine. First, I spotted that the program does something wrong in routine called Validate:<BR /> <BR /><CODE>integer function Validate(iValid)</CODE><BR /> <BR />which was called as:<BR /> <BR /><CODE>j = Validate(VALID_TOPOLOGY)</CODE><BR /> <BR />The argument is declared as:<BR /> <BR /><CODE>integer, parameter:: VALID_TOPOLOGY = 1</CODE><BR /> <BR />When I inspected value of iValid argument in the debugger, it was 47, which was meaningless. Hmmm, strange. I had to insert a "sanity check" line immediately before the call:<BR /> <BR /><CODE>idummy = VALID_TOPOLOGY</CODE><BR /> <BR />I rebuilt the application, and checked value of idummy in the debugger. It was 1 as expected. However, value of iValid was still 47. Have you seen "A Beautiful Mind?" :-)<BR /> <BR /><I>(...an hour later)</I><BR /> <BR />The source of the problem lied in the call few dozen lines before the crazy one. Another routine was called like<BR /> <BR /><CODE>call e_sin_ostrva(ierror,1)</CODE><BR /> <BR />It actually changed the value of constant "1" to 47. Compiler saw that the constant with value 1 was used twice as argument in the same routine (once as literal, once as PARAMETER), so it decided to reuse the same memory location, thus VALID_TOPOLOGY become 47. But then, how didn't it show in my "sanity check" line? Simply, compiler saw that I'm assigning a constant to a variable so it didn't bother to actually do the copying from one memory location to another; instead, it just translated the line as j=1. <BR /> <BR />Jugoslav Mon, 22 Apr 2002 17:47:41 GMT Jugoslav_Dujic 2002-04-22T17:47:41Z https://community.intel.com/t5/Software-Archive/Lost-Memory/m-p/988218#M27679 What's wrong if a declared constant can't hold its value (i.e. it changes to zero after some times) throughout the program execution? . Sat, 20 Apr 2002 19:00:51 GMT https://community.intel.com/t5/Software-Archive/Lost-Memory/m-p/988218#M27679 elf 2002-04-20T19:00:51Z https://community.intel.com/t5/Software-Archive/Lost-Memory/m-p/988219#M27680 You have Windows 9X, passed the constant as an argument to a routine and that routine changed the value of the argument.<BR /><BR />Steve Sat, 20 Apr 2002 21:40:52 GMT https://community.intel.com/t5/Software-Archive/Lost-Memory/m-p/988219#M27680 Steven_L_Intel1 2002-04-20T21:40:52Z https://community.intel.com/t5/Software-Archive/Lost-Memory/m-p/988220#M27681 Yes, that could cause various nasty behaviours. I feel inclined to write a debugging anecdote of mine. First, I spotted that the program does something wrong in routine called Validate:<BR /> <BR /><CODE>integer function Validate(iValid)</CODE><BR /> <BR />which was called as:<BR /> <BR /><CODE>j = Validate(VALID_TOPOLOGY)</CODE><BR /> <BR />The argument is declared as:<BR /> <BR /><CODE>integer, parameter:: VALID_TOPOLOGY = 1</CODE><BR /> <BR />When I inspected value of iValid argument in the debugger, it was 47, which was meaningless. Hmmm, strange. I had to insert a "sanity check" line immediately before the call:<BR /> <BR /><CODE>idummy = VALID_TOPOLOGY</CODE><BR /> <BR />I rebuilt the application, and checked value of idummy in the debugger. It was 1 as expected. However, value of iValid was still 47. Have you seen "A Beautiful Mind?" :-)<BR /> <BR /><I>(...an hour later)</I><BR /> <BR />The source of the problem lied in the call few dozen lines before the crazy one. Another routine was called like<BR /> <BR /><CODE>call e_sin_ostrva(ierror,1)</CODE><BR /> <BR />It actually changed the value of constant "1" to 47. Compiler saw that the constant with value 1 was used twice as argument in the same routine (once as literal, once as PARAMETER), so it decided to reuse the same memory location, thus VALID_TOPOLOGY become 47. But then, how didn't it show in my "sanity check" line? Simply, compiler saw that I'm assigning a constant to a variable so it didn't bother to actually do the copying from one memory location to another; instead, it just translated the line as j=1. <BR /> <BR />Jugoslav Mon, 22 Apr 2002 17:47:41 GMT https://community.intel.com/t5/Software-Archive/Lost-Memory/m-p/988220#M27681 Jugoslav_Dujic 2002-04-22T17:47:41Z https://community.intel.com/t5/Software-Archive/Lost-Memory/m-p/988221#M27682 The reason why Windows 9X is important is that it ignores the compiler's request to make constants read-only. Windows NT/2000/XP do the right thing.<BR /><BR />Steve Mon, 22 Apr 2002 22:35:25 GMT https://community.intel.com/t5/Software-Archive/Lost-Memory/m-p/988221#M27682 Steven_L_Intel1 2002-04-22T22:35:25Z