10 ms·

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

by Yacoby 12y ago

pjmlp 12y 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.
- pjc50 12y ago
  Wrong, it's defined: http://stackoverflow.com/questions/6084218/is-it-good-practice-to-free-a-null-pointer-in-c http://stackoverflow.com/questions/6084218/is-it-good-practi... You didn't say which version of the ANSI C specification.
  - masklinn 12y ago
    > 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 http://port70.net/~nsz/c/c89/c89-draft.html#4.10.3.2
    - pjmlp 12y ago
      > 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.
- masklinn 12y 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. ?
- caf 12y 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.
blt 12y ago
but it probably costs a stack frame right? ;)

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

by Yacoby 12y ago

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

pjmlp 12y 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.

pjc50 12y ago
Wrong, it's defined: http://stackoverflow.com/questions/6084218/is-it-good-practice-to-free-a-null-pointer-in-c http://stackoverflow.com/questions/6084218/is-it-good-practi... You didn't say which version of the ANSI C specification.
- masklinn 12y ago
  > 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 http://port70.net/~nsz/c/c89/c89-draft.html#4.10.3.2
  - pjmlp 12y ago
    > 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.
masklinn 12y 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. ?
caf 12y 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.

blt 12y ago

but it probably costs a stack frame right? ;)