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Fix strnlen doc re array size

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* manual/string.texi: For strnlen (s, maxlen), do not say that s must
be of size maxlen, as it can be smaller if it is null-terminated.
This should help avoid confusion such as seen in
<https://lists.gnu.org/r/bug-gnulib/2024-06/msg00280.html>.
Mention that strnlen and wcsnlen have been in POSIX since
POSIX.1-2008.
This commit is contained in:
Paul Eggert 2024-06-26 16:14:26 +01:00
parent 07fe71f59b
commit b79238db4a
1 changed files with 10 additions and 7 deletions
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17
manual/string.texi
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@ -309,12 +309,12 @@ This function was introduced in @w{Amendment 1} to @w{ISO C90}.
@end deftypefun @end deftypefun
@deftypefun size_t strnlen (const char *@var{s}, size_t @var{maxlen}) @deftypefun size_t strnlen (const char *@var{s}, size_t @var{maxlen})
@standards{GNU, string.h} @standards{POSIX.1, string.h}
@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
If the array @var{s} of size @var{maxlen} contains a null byte, This returns the offset of the first null byte in the array @var{s},
the @code{strnlen} function returns the length of the string @var{s} in except that it returns @var{maxlen} if the first @var{maxlen} bytes
bytes. Otherwise it are all non-null.
returns @var{maxlen}. Therefore this function is equivalent to Therefore this function is equivalent to
@code{(strlen (@var{s}) < @var{maxlen} ? strlen (@var{s}) : @var{maxlen})} @code{(strlen (@var{s}) < @var{maxlen} ? strlen (@var{s}) : @var{maxlen})}
but it but it
is more efficient and works even if @var{s} is not null-terminated so is more efficient and works even if @var{s} is not null-terminated so
@ -328,7 +328,9 @@ strnlen (string, 5)
@result{} 5 @result{} 5
@end smallexample @end smallexample
This function is a GNU extension and is declared in @file{string.h}. This function is part of POSIX.1-2008 and later editions, but was
available in @theglibc{} and other systems as an extension long before
it was standardized. It is declared in @file{string.h}.
@end deftypefun @end deftypefun
@deftypefun size_t wcsnlen (const wchar_t *@var{ws}, size_t @var{maxlen}) @deftypefun size_t wcsnlen (const wchar_t *@var{ws}, size_t @var{maxlen})
@ -337,7 +339,8 @@ This function is a GNU extension and is declared in @file{string.h}.
@code{wcsnlen} is the wide character equivalent to @code{strnlen}. The @code{wcsnlen} is the wide character equivalent to @code{strnlen}. The
@var{maxlen} parameter specifies the maximum number of wide characters. @var{maxlen} parameter specifies the maximum number of wide characters.
This function is a GNU extension and is declared in @file{wchar.h}. This function is part of POSIX.1-2008 and later editions, and is
declared in @file{wchar.h}.
@end deftypefun @end deftypefun
@node Copying Strings and Arrays @node Copying Strings and Arrays