manual: Document stdio.h functions that may be macros

Glibc has two gnu-extension functions that are implemented as
macros but not documented as such: fread_unlocked and
fwrite_unlocked.  Document them as such.

Additionally, putc_unlocked and getc_unlocked are documented in
POSIX as possibly being macros.  Update the manual to add a warning
about those also, depite glibc not implementing them as macros.
This commit is contained in:
DJ Delorie 2024-10-10 17:16:35 -04:00
parent b371ed2726
commit dcad785074

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@ -929,6 +929,9 @@ Therefore, @var{stream} should never be an expression with side-effects.
@safety{@prelim{}@mtsafe{@mtsrace{:stream}}@asunsafe{@asucorrupt{}}@acunsafe{@acucorrupt{}}}
The @code{putc_unlocked} function is equivalent to the @code{putc}
function except that it does not implicitly lock the stream.
Like @code{putc}, it may be implemented as a macro and may evaluate
the @var{stream} argument more than once. Therefore, @var{stream}
should not be an expression with side-effects.
@end deftypefun
@deftypefun wint_t putwc_unlocked (wchar_t @var{wc}, FILE *@var{stream})
@ -1132,6 +1135,9 @@ Therefore, @var{stream} should never be an expression with side-effects.
@safety{@prelim{}@mtsafe{@mtsrace{:stream}}@asunsafe{@asucorrupt{}}@acunsafe{@acucorrupt{}}}
The @code{getc_unlocked} function is equivalent to the @code{getc}
function except that it does not implicitly lock the stream.
Like @code{getc}, it may be implemented as a macro and may evaluate
the @var{stream} argument more than once. Therefore, @var{stream}
should not be an expression with side-effects.
@end deftypefun
@deftypefun wint_t getwc_unlocked (FILE *@var{stream})
@ -1571,6 +1577,9 @@ The @code{fread_unlocked} function is equivalent to the @code{fread}
function except that it does not implicitly lock the stream.
This function is a GNU extension.
This function may be implemented as a macro and may evaluate
@var{stream} more than once. Therefore, @var{stream} should not be an
expression with side-effects.
@end deftypefun
@deftypefun size_t fwrite (const void *@var{data}, size_t @var{size}, size_t @var{count}, FILE *@var{stream})
@ -1589,6 +1598,9 @@ The @code{fwrite_unlocked} function is equivalent to the @code{fwrite}
function except that it does not implicitly lock the stream.
This function is a GNU extension.
This function may be implemented as a macro and may evaluate
@var{stream} more than once. Therefore, @var{stream} should not be an
expression with side-effects.
@end deftypefun
@node Formatted Output