diff options
Diffstat (limited to 'lib/libvgl')
| -rw-r--r-- | lib/libvgl/vgl.3 | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/lib/libvgl/vgl.3 b/lib/libvgl/vgl.3 index a65aa00..187dd61 100644 --- a/lib/libvgl/vgl.3 +++ b/lib/libvgl/vgl.3 @@ -408,6 +408,54 @@ blank the display if the argment .Va blank != 0. This can be done to shut off the screen during display updates that the user should first see when it's done. +.Ss Program termination and signal processing +It is important to call +.Fn VGLEnd +before terminating the program. +Care must be taken if you install signal handlers and try to call +.Fn VGLEnd +and +.Xr exit 3 +to end the program. +If a signal is caught while the program is inside +.Nm libvgl +functions, +.Fn VGLEnd +may not be able to properly restore the graphics hardware. +.Pp +The recommended way to handle signals and program termination is to +have a flag to indicate singnal's delivery. +Your singnal handlers set this flag but do not terminate +the program immediately. +The main part of the program checks the flag to see if it is +supporsed to terminate, and call +.Fn VGLEnd +and +.Xr exit 3 +if the flag is set. +.Pp +Note that +.Fn VGLInit +installs its internal signal handlers for +.Dv SIGINT , SIGTERM , SIGSEGV , +and +.Dv SIGBUS , +and terminates the program at appropriate time, +after one of these signals is caught. +If you want to have your own signal handlers for these signals, +install handers +.Em after +.Fn VGLInit . +.Pp +.Dv SIGUSR1 +and +.Dv SIGUSR2 +are internally used by +.Nm libvgl +to control screen switching and the mouse pointer, +and are not available to +.Nm libvgl +client programs. .Sh AUTHORS .An S\(/oren Schmidt Aq sos@FreeBSD.org .Sh HISTORY |
