diff options
Diffstat (limited to 'lib/libc/sys/select.2')
| -rw-r--r-- | lib/libc/sys/select.2 | 44 |
1 files changed, 26 insertions, 18 deletions
diff --git a/lib/libc/sys/select.2 b/lib/libc/sys/select.2 index 3de5b5e..c9a332dc 100644 --- a/lib/libc/sys/select.2 +++ b/lib/libc/sys/select.2 @@ -104,7 +104,7 @@ If is a non-nil pointer, it specifies a maximum interval to wait for the selection to complete. If .Fa timeout -is a nil pointer, the select blocks indefinitely. To affect a poll, the +is a nil pointer, the select blocks indefinitely. To effect a poll, the .Fa timeout argument should be non-nil, pointing to a zero-valued timeval structure. .Pp @@ -140,6 +140,9 @@ before any of the selected events occurred. .It Bq Er EINVAL The specified time limit is invalid. One of its components is negative or too large. +.It Bq Er EINVAL +.Fa nfds +was invalid. .El .Sh SEE ALSO .Xr accept 2 , @@ -149,26 +152,31 @@ negative or too large. .Xr read 2 , .Xr recv 2 , .Xr send 2 , -.Xr write 2 -.Sh BUGS -Although the provision of -.Xr getdtablesize 2 -was intended to allow user programs to be written independent -of the kernel limit on the number of open files, the dimension -of a sufficiently large bit field for select remains a problem. -The default size +.Xr write 2 , +.Xr clocks 7 +.Sh NOTES +The default size of .Dv FD_SETSIZE -(currently 256) is somewhat larger than -the current kernel limit to the number of open files. -However, in order to accommodate programs which might potentially -use a larger number of open files with select, it is possible -to increase this size within a program by providing -a larger definition of +is currently 256. +In order to accomodate programs which might potentially +use a larger number of open files with +.Fn select +, it is possible +to increase this size by having the program define .Dv FD_SETSIZE -before the inclusion of +before the inclusion of any header which includes .Aq Pa sys/types.h . .Pp -.Fn Select +If +.Fa nfds +is greater than the number of open files, +.Fn select +is not guaranteed to examine the unused file descriptors. For historical +reasons, +.Fn select +will always examine the first 256 descriptors. +.Sh BUGS +.Fn select should probably return the time remaining from the original timeout, if any, by modifying the time value in place. This may be implemented in future versions of the system. @@ -178,6 +186,6 @@ by the call. .Sh HISTORY The -.Nm +.Fn select function call appeared in .Bx 4.2 . |
