diff options
Diffstat (limited to 'man2')
| -rw-r--r-- | man2/mmap.2 | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/man2/mmap.2 b/man2/mmap.2 index 9393294c62..6133910583 100644 --- a/man2/mmap.2 +++ b/man2/mmap.2 @@ -635,9 +635,11 @@ Use of a mapped region can result in these signals: Attempted write into a region mapped as read-only. .TP .B SIGBUS -Attempted access to a portion of the buffer that does not correspond -to the file (for example, beyond the end of the file, including the -case where another process has truncated the file). +Attempted access to a page of the buffer that lies beyond the +end of the mapped file. +For an explanation of the treatment of the bytes in the page that +corresponds to the end of a mapped file that is not a multiple +of the page size, see NOTES. .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). @@ -678,8 +680,10 @@ with the same attributes. .PP A file is mapped in multiples of the page size. For a file that is not -a multiple of the page size, the remaining memory is zeroed when mapped, -and writes to that region are not written out to the file. +a multiple of the page size, +the remaining bytes in the partial page at the end of the mapping +are zeroed when mapped, +and modifications to that region are not written out to the file. The effect of changing the size of the underlying file of a mapping on the pages that correspond to added or removed regions of the file is unspecified. |