strcpy() return value

c function strcpy
Blagovest Buyukliev picture Blagovest Buyukliev · Aug 25, 2010 · Viewed 20.5k times · Source

A lot of the functions from the standard C library, especially the ones for string manipulation, and most notably strcpy(), share the following prototype:

char *the_function (char *destination, ...)

The return value of these functions is in fact the same as the provided destination. Why would you waste the return value for something redundant? It makes more sense for such a function to be void or return something useful.

My only guess as to why this is is that it's easier and more convenient to nest the function call in another expression, for example:

printf("%s\n", strcpy(dst, src));

Are there any other sensible reasons to justify this idiom?

Answer

nothrow picture nothrow · Aug 25, 2010

as Evan pointed out, it is possible to do something like

char* s = strcpy(malloc(10), "test");

e.g. assign malloc()ed memory a value, without using helper variable.

(this example isn't the best one, it will crash on out of memory conditions, but the idea is obvious)

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