Errors in two Section 3 functions

Errors in two Section 3 functions

[Rick Stanley]

Hello!

I have noticed two errors for memmove() and memcpy().

memmove():

man7.org:
"void *memmove(size_t n;
                     void dest[n], const void src[n], size_t n);"
string.h:
"extern void *memmove (void *__dest, const void *__src, size_t __n)"
(Leaving off the __THROW text)


memcpy()

man7.org:
"void *memcpy(size_t n;
                    void dest[restrict n], const void src[restrict n],
                    size_t n);"

string.h:
"extern void *memccpy (void *__restrict __dest, const void *__restrict
__src, int __c, size_t __n)"

The issue in both is:
"memmove(size_t n;"
"memcpy(size_t n;"

IMHO on man7.org, they should read:

"void *memmove(void dest[n], const void src[n], size_t n);"

"void *memcpy(void dest[restrict n], const void src[restrict n],
 size_t n);"

Thanks!

Rick

-- 
Rick Stanley
(917) 822-7771
www.rsiny.com
IT  Consulting
Linux & Open Source Specialist

Re: Errors in two Section 3 functions

[Alejandro Colomar]

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Hi Rick,

On Sun, Nov 02, 2025 at 10:47:47AM -0500, Rick Stanley wrote:
> Hello!
> 
> I have noticed two errors for memmove() and memcpy().
> 
> memmove():
> 
> man7.org:
> "void *memmove(size_t n;
>                      void dest[n], const void src[n], size_t n);"
> string.h:
> "extern void *memmove (void *__dest, const void *__src, size_t __n)"
> (Leaving off the __THROW text)
> 
> 
> memcpy()
> 
> man7.org:
> "void *memcpy(size_t n;
>                     void dest[restrict n], const void src[restrict n],
>                     size_t n);"
> 
> string.h:
> "extern void *memccpy (void *__restrict __dest, const void *__restrict
> __src, int __c, size_t __n)"
> 
> The issue in both is:
> "memmove(size_t n;"
> "memcpy(size_t n;"

That's not an error; it's valid GNU C.

> IMHO on man7.org, they should read:
> 
> "void *memmove(void dest[n], const void src[n], size_t n);"
> 
> "void *memcpy(void dest[restrict n], const void src[restrict n],
>  size_t n);"

That would be incorrect.  You can't use a variable before declaring it.
See <https://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html>.


Have a lovely night!
Alex

-- 
<https://www.alejandro-colomar.es>
Use port 80 (that is, <...:80/>).

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