undefined | Better HN

0 pointspjmlp11y ago0 comments

By worse do you mean?

    #define new(x) (malloc(sizeof(x)))
    #define dispose(x) { if((x) != NULL) { free(x); } }

C was so primitive already when compared against Turbo Pascal 6.0

0 comments

Yacoby11y ago

Totally worse. free(NULL) preforms no action so there is no requirement for the if statement. ;)

blt11y ago

but it probably costs a stack frame right? ;)

pjmlpOP11y ago

Except free(NULL) behavior is undefined.

Have you ever bothered to read ANSI C specification?

EDIT: Well it appears my recollections of ANSI C have faded away and free(NULL) was actually defined in ANSI C89.

masklinn11y ago

> Except free(NULL) behavior is undefined.

> Have you ever bothered to read ANSI C specification?

You mean the one that states

> The free function causes the space pointed to by ptr to be deallocated, that is, made available for further allocation. If ptr is a null pointer, no action occurs.

pjc5011y ago

Wrong, it's defined: http://stackoverflow.com/questions/6084218/is-it-good-practi...

You didn't say which version of the ANSI C specification.

1 more reply

caf11y ago

It's been defined ever since the original ANSI C, which said this in the definition of free():

  If ptr is a null pointer, no action occurs.

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