Re: [9front] etimer() assumes seconds together with APE

[Steve Simon <steve@quintile.net>]

this brings back memories of the libplot on v7 unix, which had a close() entrypoint.

you had to link your app in two stages. the graphics stuff got bound to libplot with -r to keep the relocation data, then the result linked with the remainder of the app.

history just keeps repeating.

-Steve


> On 12 May 2020, at 5:10 pm, jamos@oboj.net wrote:
> 
> Dear list,
> 
> The function etimer(ulong key, int n) is used in libevent to get a timer event every 'n' milliseconds. However, if APE is used, etimer() delivers an event every 'n' second instead. The reason is that sleep() assumes seconds in APE and milliseconds in Plan 9.
> 
> I am aware that combining Plan 9 libraries with APE is a bit risky. When I earlier wanted to use etimer() in the netsurf framebuffer driver, I assumed it didn't work under APE, but I was not patient enough to wait 1000 seconds, when I thought it would fire after one second.
> 
> Would this be considered a bug? It would be more consistent if etimer() would take milliseconds as well under APE, and it would also be more handy if one would like to sleep less than a second. I tried to find APE programs that might depend on the current behaviour, but I don't think there are many.
> 
> The following test program prints a string every 10 seconds (in APE) and every 10ms (if it can manage) under native Plan9. Stop by killing the processes.
> 
> /* Compile under native plan9:
> *    8c ev.c; 8l -o native ev.8
> *
> * Compile under APE:
> *    pcc  -D_POSIX_SOURCE -D_PLAN9_SOURCE -o posix ev.c
> */
> 
> #include <u.h>
> #ifdef _POSIX_SOURCE
>    #include <stdlib.h>
> #else
>    #include <libc.h>
> #endif
> #include <draw.h>
> #include <event.h>
> 
> void
> eresized(int) {}
> 
> void
> main()
> {
>    int tim;    /* timer ticket */
>    int e;        /* type of event */
>    Event ev;    /* event struct */
> 
>    initdraw(0, 0, "timer test");
>    einit(Ekeyboard|Emouse);
>    tim = etimer(0, 10);    /* 10ms or 10s?*/
>    for(;;){
>        e = event(&ev);
>        if(e == tim)
>            print("Timer!\n");
> 
>    }
> }