Why doesn't this work?

[Guest_imported]

Can someone give me the official reason this doesn't work in C using Visual C++. It works in C in Unix environments but crashes in a simple VC++ console application. The answer should be obvious but I don't see it.

char somevar[20];

strcpy( somevar, (char *)NULL);

Thanks in advance.

 

[rbobbitt]

Because strcpy() expects a const char * for its 2nd argument, not NULL.

The C standard doesn't define what happens when you pass strcpy() a NULL argument, so a crash is quite appropriate.

If you're trying to initialize somevar to an "empty string," do this:

char somevar[20]={0};

This has the effect of setting all the bytes in somevar to '\0'.

Only pointers should be assigned NULL anyway, which is totally different from the null character '\0' that terminates strings.

Russ
bobbitts@hotmail.com

http://home.earthlink.net/~bobbitts

 

[Guest_imported]

Thanks, Russ. I suspected something along those lines but wanted to hear it from an expert.

Brian

 

[rbobbitt]

Well, you didn't hear it from an expert, but you heard it anyway ;-) ... it will be some time I suspect before I begin to consider myself an *expert* in C.

Russ
bobbitts@hotmail.com

http://home.earthlink.net/~bobbitts