From: John Hubbard <jhubbard@xxxxxxxxxx> MAP_FIXED has been widely used for a very long time, yet the man page still claims that "the use of this option is discouraged". The documentation assumes that "less portable" == "must be discouraged". Instead of discouraging something that is so useful and widely used, change the documentation to explain its limitations better. Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx> --- While reviewing Michal Hocko's man page update for MAP_FIXED_SAFE, I noticed that MAP_FIXED was no longer reflecting the current situation, so here is a patch to bring it into the year 2017. man2/mmap.2 | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/man2/mmap.2 b/man2/mmap.2 index 385f3bfd5..a5a8eb47a 100644 --- a/man2/mmap.2 +++ b/man2/mmap.2 @@ -222,8 +222,10 @@ part of the existing mapping(s) will be discarded. If the specified address cannot be used, .BR mmap () will fail. -Because requiring a fixed address for a mapping is less portable, -the use of this option is discouraged. +Software that aspires to be portable should use this option with care, keeping +in mind that the exact layout of a process' memory map is allowed to change +significantly between kernel versions, C library versions, and operating system +releases. .TP .B MAP_GROWSDOWN This flag is used for stacks. -- 2.15.1 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
