qiurui
/
glibc
mirror of git://sourceware.org/git/glibc.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

termios: SPEED_MAX and BAUD_MAX constants 

Add constants indicating the maximum values of speed_t and baud_t.
Hopefully if and when the baud_t interface is standardized then
BAUD_MAX will be included in the standardization from the start.

Historically, the __MAX_BAUD symbol has indicated the maximum speed_t
value on at least some platforms (including glibc).  However, this
name would be problematic for future standardization, because it
confusingly implies a reference to baud_t, not speed_t, and it is
inconsistent with other limit symbols, which are all of the form *_MAX
(e.g. SIZE_MAX for size_t.)

[ v3: dropped leading underscores, leave __MAX_BAUD outside
      #ifdef __USE_MISC since it is a legacy symbol, and
      namespace-protected with a double underscore.
      (Collin Funk, Adhermerval Zanella Netto) ]

[ v4: moved from __USE_MISC to __USE_GNU (Collin Funk) ]

Signed-off-by: "H. Peter Anvin" (Intel) <hpa@zytor.com>
Reviewed-by: Collin Funk <collin.funk1@gmail.com>
This commit is contained in:
H. Peter Anvin 2025-07-12 22:19:43 -07:00 committed by Andreas K. Hüttel
parent 0332959dd2
commit 12126f86f2
No known key found for this signature in database
GPG Key ID: DC2B16215ED5412A
2 changed files with 5 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
bits/termios-baud.h
View File

@ -69,4 +69,7 @@
#define B5000000 5000000U
#define B10000000 10000000U
#define __MAX_BAUD 4294967295U
#ifdef __USE_GNU
#define SPEED_MAX 4294967295U /* maximum valid speed_t value */
#endif
#define __MAX_BAUD 4294967295U /* legacy alias for SPEED_MAX */

1
termios/termios.h
View File

@ -64,6 +64,7 @@ extern int cfsetspeed (struct termios *__termios_p, speed_t __speed) __THROW;
#ifdef __USE_GNU
/* Interfaces that are explicitly numeric representations of baud rates */
typedef speed_t baud_t;
#define BAUD_MAX SPEED_MAX
/* Return the output baud rate stored in *TERMIOS_P. */
extern baud_t cfgetobaud (const struct termios *__termios_p) __THROW;