Return to shrchild.c CVS log

Up to [OS/2 SDKs] / os2sdk / demos / examples / share

Annotation of os2sdk/demos/examples/share/shrchild.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * This is the child process exec'd asynchronously from the child.c.
                      3:  */
                      4: 
                      5: #include <doscalls.h>          /* necessary whenever doscalls are made */
                      6: #include "share.h"             /* common shared memory declarations */
                      7: 
                      8: main()
                      9: {
                     10:        unsigned                Selector;
                     11:        unsigned                rc;             /* return code */
                     12:        unsigned                nBytes;
                     13:        char                    c;
                     14:        struct ShareRec         *SmemPtr;       /* shared memory pointer */
                     15: 
                     16:        /* get selector to the shared memory segment defined in parent */
                     17: 
                     18:        if (rc = DOSGETSHRSEG( (char *) SHRSEGNAME,
                     19:                               (unsigned *) &Selector ))  {
                     20:                DOSEXIT(1, 0);
                     21:        }
                     22: 
                     23:        /* Get a far pointer from a 16 bit selector */
                     24: 
                     25:        SmemPtr = (struct ShareRec *) GETSEGPTR(Selector, 0);
                     26:        
                     27:        for (;;) {
                     28: 
                     29:            /* block if buffer empty */
                     30:            DOSSEMWAIT((long)&(SmemPtr->emptysem), WAITFOREVER);
                     31: 
                     32:            /* mutual exclusion on buffer pointers */
                     33:            DOSSEMREQUEST((long)&(SmemPtr->mutexsem), WAITFOREVER);
                     34:            c = SmemPtr->CircBuffer[SmemPtr->tail];     /* get next char */
                     35:            SmemPtr->tail++;                /* step pointer */
                     36:            SmemPtr->tail %= CIRCBUFSIZE;   /* wrap at end  */
                     37:            if (SmemPtr->tail == SmemPtr->head)
                     38:                DOSSEMSET((long)&(SmemPtr->emptysem));
                     39:            DOSSEMCLEAR((long)&(SmemPtr->mutexsem));
                     40: 
                     41:            DOSSEMCLEAR((long)&(SmemPtr->fullsem));
                     42: 
                     43:            DOSWRITE( 1, (char *) &c, 1, &nBytes );     /* display next char */
                     44:            DOSSLEEP(1000L);    /* max 1 per sec to demo buffering & sems */
                     45:        }
                     46: }

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.