[doctorwho]

All the Pascal fanboys did this (and worse) before they gave in and finally converted :)

#define begin {

#define end }

[cbd1984]

The source code to the original Bourne shell did that and a lot worse. It became one of the inspirations for the IOCCC (International Obfuscated C Code Competition).

http://www.ioccc.org/faq.html

(What that FAQ doesn't mention is the real reason the Bourne shell deserved to be in the IOCCC: The way it allocated memory. It trapped SIGSEGV (the signal the kernel sends you when you've provoked a segmentation violation or segfault by trying to access memory you don't own) so it would know when to request more RAM from the OS. This later became a problem for people looking to port the Bourne shell, for example to the Motorola 68000 CPUs which powered the first generation of Unix workstations.

http://www.in-ulm.de/~mascheck/bourne/segv.html )

[anatoly]

That's an amazing story, thanks! This is the place where it catches the fault: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V7/usr/src/cmd/...

[0942v8653]

Here's the IF/FI #defines: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V7/usr/src/cmd/...

[pjmlp]

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

[Yacoby]

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

[blt]

but it probably costs a stack frame right? ;)

[pjmlp]

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.

[masklinn]

> 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.

?

[pjc50]

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

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

[masklinn]

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

Which does not matter because all of them clearly define the behavior of free(NULL). The language has been the same since C89[0]:

> 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.

I'm guessing pjmlp confused free(NULL) which is defined and double free which is UB:

> if the argument does not match a pointer earlier returned by the calloc , malloc , or realloc function, or if the space has been deallocated by a call to free or realloc , the behavior is undefined.

and didn't "bother to read the ANSI C specification" because he was so certain of what he misremembered.

[0] http://port70.net/~nsz/c/c89/c89-draft.html#4.10.3.2

[pjmlp]

> and didn't "bother to read the ANSI C specification" because he was so certain of what he misremembered.

Yes, it appears my recollections of ANSI C have faded away.

[caf]

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.

[thaumaturgy]

Hah, yep. I remember giving that a whirl not long before I gave up on Pascal, and looking at my screen and being completely horrified by the result.