Q45230: Conflict between Global and Local Variables When Debugging

Article: Q45230
Product(s): See article
Version(s): 2.00
Operating System(s): MS-DOS
Keyword(s): ENDUSER | buglist2.00 | mspl13_c
Last Modified: 13-SEP-1989

The Microsoft QuickC Version 2.00 integrated debugger has a problem if
a global variable in one source file has the same name as a local
variable in another source file and that function has a printf()
function call. The easiest workaround is to rename one of the
variables. A problem description is given below.

Microsoft has confirmed this to be a problem with the Microsoft QuickC
Compiler Version 2.00. We are researching this problem and will post
new information as it becomes available.

The following two source files demonstrate this problem. To reproduce
the problem, compile and link the two source files together. Step to
the first executable line in the program and set a watch on the "foo"
variable. Now step through the program and notice that the debugger
does not show the correct value of foo after the assignment, although
the sub() function will be called.

Source File Example 1
---------------------

/* main.c */
extern void sub(void);
int foo;
main() {
    foo = 20;
    if (foo == 20) sub();
}

/* sub.c */
#include <stdio.h>
void sub(void) {
    int foo;
    printf("test");
}

To get around this problem, rename one of the offending variables,
remove the printf() from the sub() function, or add another assignment
to any global variable before the "foo = 20;" line in the main()
function.

Source File Example 2
---------------------

/* main.c */
extern void sub(void);
int foo,temp;
main() {
    temp = 20;      /* could also say "foo = 20;" */
    foo = 20;
    if (foo == 20) sub();
}

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