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Dear all,
in my program i declared some variable as constant. After compilation this program gives me some problem related to above declare variable.
Moment i remove constant from those variable my program start working correctly.
I am inital stage of debugging. Please suggest area where i need to see to solve problem.
Regards..
Yogesh
"make sure that you don't try to write to it somewhere in the program."
If it's declared as 'const', the compiler should give a warning about any attempt to write to it - unless it's some indirect access that the compiler can't detect at compile-time...
Yes, but it is quite easy to take the address of a const variable and send into a library function that drops the const (more than one library function have had the problem that they have taken a pointer to a const variable as input parameter, and returned a pointer to a non-const variable.
It is also much too common that people make type casts to avoid signed/unsigned warnings, and at the same time looses extra attributes, such as const.
Erik: A const variable may sound a bit strange, but since the value is actually having a memory address it is completely different from a numeric literal constant or an enumerated value or a #defined value. In a number of environments, const variables are not stored in write-protected memory, so the application may add a typecast and then use it as a normal variable.
The term "variable" is not really a 'C' thing - it is not mentioned in the 'C' standard - the term used is "identifier"
This avoids the contradictory term "constant variable".
No, an identifier is not the same thing as a variable, since an identifier is a superset that includes functions, data types etc.
"an identifier is not the same thing as a variable"
True; it would need to be specifically a data identifier - but 'C' still doesn't officially use the term "variable", as in some other languages (eg, BASIC).