manual/stdio: Further clarify putc, putwc, getc, and getwc

This is a follow-up to 10de4a47ef3f481592e3c62eb07bcda23e9fde4d that
reworded the manual entries for putc and putwc and removed any
performance claims.

This commit further clarifies these entries and brings getc and getwc in
line with the descriptions of putc and putwc, removing any performance
claims from them as well.
Reviewed-by: Florian Weimer <fweimer@redhat.com>

(cherry picked from commit 942670c81dc8071dd75d6213e771daa5d2084cb6)

1 files changed, 10 insertions, 17 deletions

diff --git a/manual/stdio.texi b/manual/stdio.texi
index c11d37b363..0b31aeff95 100644
--- a/manual/stdio.texi
+++ b/manual/stdio.texi
@@ -904,20 +904,16 @@ This function is a GNU extension.
 @standards{ISO, stdio.h}
 @safety{@prelim{}@mtsafe{}@asunsafe{@asucorrupt{}}@acunsafe{@acucorrupt{} @aculock{}}}
 This is just like @code{fputc}, except that it may be implemented as
-a macro, making it faster.  One consequence is that it may evaluate the
-@var{stream} argument more than once, which is an exception to the
-general rule for macros.  Therefore, @var{stream} should never be an
-expression with side-effects.
+a macro and may evaluate the @var{stream} argument more than once.
+Therefore, @var{stream} should never be an expression with side-effects.
 @end deftypefun
 
 @deftypefun wint_t putwc (wchar_t @var{wc}, FILE *@var{stream})
 @standards{ISO, wchar.h}
 @safety{@prelim{}@mtsafe{}@asunsafe{@asucorrupt{}}@acunsafe{@acucorrupt{} @aculock{}}}
 This is just like @code{fputwc}, except that it may be implemented as
-a macro, making it faster.  One consequence is that it may evaluate the
-@var{stream} argument more than once, which is an exception to the
-general rule for macros.  Therefore, @var{stream} should never be an
-expression with side-effects.
+a macro and may evaluate the @var{stream} argument more than once.
+Therefore, @var{stream} should never be an expression with side-effects.
 @end deftypefun
 
 @deftypefun int putc_unlocked (int @var{c}, FILE *@var{stream})
@@ -1110,20 +1106,17 @@ This function is a GNU extension.
 @deftypefun int getc (FILE *@var{stream})
 @standards{ISO, stdio.h}
 @safety{@prelim{}@mtsafe{}@asunsafe{@asucorrupt{}}@acunsafe{@aculock{} @acucorrupt{}}}
-This is just like @code{fgetc}, except that it is permissible (and
-typical) for it to be implemented as a macro that evaluates the
-@var{stream} argument more than once.  @code{getc} is often highly
-optimized, so it is usually the best function to use to read a single
-character.
+This is just like @code{fgetc}, except that it may be implemented as
+a macro and may evaluate the @var{stream} argument more than once.
+Therefore, @var{stream} should never be an expression with side-effects.
 @end deftypefun
 
 @deftypefun wint_t getwc (FILE *@var{stream})
 @standards{ISO, wchar.h}
 @safety{@prelim{}@mtsafe{}@asunsafe{@asucorrupt{}}@acunsafe{@aculock{} @acucorrupt{}}}
-This is just like @code{fgetwc}, except that it is permissible for it to
-be implemented as a macro that evaluates the @var{stream} argument more
-than once.  @code{getwc} can be highly optimized, so it is usually the
-best function to use to read a single wide character.
+This is just like @code{fgetwc}, except that it may be implemented as
+a macro and may evaluate the @var{stream} argument more than once.
+Therefore, @var{stream} should never be an expression with side-effects.
 @end deftypefun
 
 @deftypefun int getc_unlocked (FILE *@var{stream})