what is question mark(?)?

[Intel_C_Intel]

Hi, I am an ifc compiler user, actually. Two weeks ago, I faced with a strange error, may be some users of icc have an experience of such an error: normally, ifc prints dashed lines(-) when you print out 1/0 division or it prints asterixes in format problems, moreover it print 0.00000e0 when underflow and overflow cases; the error message that I faced with is question marks(?). Normally, my program does certain calculation and prints the results in a text file, however allmost all runs of my program, that text file is filled with question marks...
Have you ever experienced such an error? If you have, it depends on what kind of programming error?
If you can help me on that subject, I would be very glad...

[Steven_L_Intel1]

If I recall correctly, ifc/ifl prints out a row of question marks to indicate an IEEE NaN (Not a Number) value. There is some other punctuation used for +Infinity and -Infinity. These will change in the next major release to be the more reasonable strings "NaN", "Inf", "-Inf", etc.

Regardless, they won't read back in. You need to find where in your program an overflow or invalid value is being computed.

Steve