diff options
Diffstat (limited to 'manual')
| -rw-r--r-- | manual/conf.texi | 2 | ||||
| -rw-r--r-- | manual/job.texi | 38 |
2 files changed, 11 insertions, 29 deletions
diff --git a/manual/conf.texi b/manual/conf.texi index dbd1d30287..f959b00bb6 100644 --- a/manual/conf.texi +++ b/manual/conf.texi @@ -156,6 +156,8 @@ supported; use @code{sysconf} to find out. @xref{Sysconf}. If this symbol is defined, it indicates that the system supports job control. Otherwise, the implementation behaves as if all processes within a session belong to a single process group. @xref{Job Control}. +Systems conforming to the 2001 revision of POSIX, or newer, will +always define this symbol. @end deftypevr @deftypevr Macro int _POSIX_SAVED_IDS diff --git a/manual/job.texi b/manual/job.texi index 944967a73d..e304313ca7 100644 --- a/manual/job.texi +++ b/manual/job.texi @@ -19,9 +19,15 @@ You need to be familiar with concepts relating to process creation Handling}) in order to understand this material presented in this chapter. +@vindex _POSIX_JOB_CONTROL +Some old systems do not support job control, but @gnusystems{} always +have, and it is a required feature in the 2001 revision of POSIX.1 +(@pxref{POSIX}). If you need to be portable to old systems, you can +use the @code{_POSIX_JOB_CONTROL} macro to test at compile-time +whether the system supports job control. @xref{System Options}. + @menu * Concepts of Job Control:: Jobs can be controlled by a shell. -* Job Control is Optional:: Not all POSIX systems support job control. * Controlling Terminal:: How a process gets its controlling terminal. * Access to the Terminal:: How processes share the controlling terminal. * Orphaned Process Groups:: Jobs left after the user logs out. @@ -29,7 +35,7 @@ chapter. * Functions for Job Control:: Functions to control process groups. @end menu -@node Concepts of Job Control, Job Control is Optional, , Job Control +@node Concepts of Job Control @section Concepts of Job Control @cindex shell @@ -102,30 +108,7 @@ jobs between foreground and background. @xref{Access to the Terminal}, for more information about I/O to the controlling terminal. -@node Job Control is Optional, Controlling Terminal, Concepts of Job Control , Job Control -@section Job Control is Optional -@cindex job control is optional - -Not all operating systems support job control. @gnusystems{} do -support job control, but if you are using @theglibc{} on some other -system, that system may not support job control itself. - -You can use the @code{_POSIX_JOB_CONTROL} macro to test at compile-time -whether the system supports job control. @xref{System Options}. - -If job control is not supported, then there can be only one process -group per session, which behaves as if it were always in the foreground. -The functions for creating additional process groups simply fail with -the error code @code{ENOSYS}. - -The macros naming the various job control signals (@pxref{Job Control -Signals}) are defined even if job control is not supported. However, -the system never generates these signals, and attempts to send a job -control signal or examine or specify their actions report errors or do -nothing. - - -@node Controlling Terminal, Access to the Terminal, Job Control is Optional, Job Control +@node Controlling Terminal @section Controlling Terminal of a Process One of the attributes of a process is its controlling terminal. Child @@ -1166,9 +1149,6 @@ The @code{setpgid} function puts the process @var{pid} into the process group @var{pgid}. As a special case, either @var{pid} or @var{pgid} can be zero to indicate the process ID of the calling process. -This function fails on a system that does not support job control. -@xref{Job Control is Optional}, for more information. - If the operation is successful, @code{setpgid} returns zero. Otherwise it returns @code{-1}. The following @code{errno} error conditions are defined for this function: |