Return to cwait.c CVS log

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

Annotation of os2sdk/demos/examples/cwait/cwait.c, revision 1.1.1.2

1.1       root        1: /*
1.1.1.2 ! root        2:  * Example of DosCWait usage.
1.1       root        3:  *
1.1.1.2 ! root        4:  * Although a process can only call DosCWait on its own child processes,
1.1       root        5:  * it is possible to wait indirectly on subsequent generations of
                      6:  * processes by use of the ProcessAndDescendents flag.  To wait for a
1.1.1.2 ! root        7:  * collection of subprocesses to end, a process must call DosCWait
1.1       root        8:  * repeatedly, once for each of the subprocesses.  The result codes
                      9:  * field is only valid for the one call first call against the child.
                     10:  * Subsequent calls indicate that another descendent process has ended,
                     11:  * but do not return exit or termination codes.
                     12:  * 
                     13:  * To wait for any child, rather that a specific one, the process
                     14:  * should pass in a process id of 0.  The pid of the process that ended
                     15:  * will be placed in the ProcessIdWord field.
                     16:  *
                     17:  * Compile as: cl -AL -G2 -Lp cwait.c
                     18:  *
1.1.1.2 ! root       19:  * Created by Microsoft Corp. 1986
1.1       root       20:  */
                     21: 
1.1.1.2 ! root       22: #define INCL_DOSPROCESS
        !            23: 
        !            24: #include <os2def.h>
        !            25: #include <bsedos.h>
1.1       root       26: #include <stdio.h>
                     27: 
                     28: #define ERRBUF_LEN     64
                     29: #define ARG_LEN                128
                     30: 
                     31: main()
                     32: {
1.1.1.2 ! root       33:        RESULTCODES child_status, child_pid;
        !            34:        PID ending_pid;
        !            35:        unsigned res;
1.1       root       36:        char errbuf[ERRBUF_LEN];
                     37:        char child_arg[ARG_LEN];
                     38:        char *child_env;
                     39: 
                     40:        /*
                     41:         * Execute a program and wait for it to finish.
                     42:         */
1.1.1.2 ! root       43:        DosExecPgm((char *)0, 0, 2, (char *)0, (char *)0, &child_pid,
1.1       root       44:                "child.exe");
                     45:        printf("exec'd child, pid = %u\n", child_pid);
1.1.1.2 ! root       46:        DosCWait(0,0, &child_status, &ending_pid, child_pid.codeTerminate);
        !            47:        if (child_status.codeTerminate != 0)
1.1       root       48:                printf("error: child's termination code was %u\n",
1.1.1.2 ! root       49:                        child_status.codeTerminate);
1.1       root       50:        else
1.1.1.2 ! root       51:                printf("child process returned %u\n", child_status.codeResult);
1.1       root       52: 
                     53:        /*
                     54:         * Execute a program and wait for it and all of its descendents
                     55:         * to finish. In this case we specify the top pid to wait for.
                     56:         */
1.1.1.2 ! root       57:        DosExecPgm((char *)0, 0, 2, (char *)0, (char *)0, &child_pid,
1.1       root       58:                "child.exe");
                     59:        printf("exec'd child, pid = %u\n", child_pid);
                     60:        do {
1.1.1.2 ! root       61:                res = DosCWait(1,0, &child_status, &ending_pid,
        !            62:                        child_pid.codeTerminate);
1.1       root       63:                if(res == 0)
                     64:                        printf("cwait found pid = %u\n", ending_pid);
                     65:                else
                     66:                        printf("cwait found no more process\n");
                     67:        } while (res == 0);
                     68:        
                     69:        /*
                     70:         * Wait for any child to terminate. In this case we specify
                     71:         * the pid as zero, which means wait for any child to finish.
                     72:         */
1.1.1.2 ! root       73:        DosExecPgm((char *)0, 0, 2, (char *)0, (char *)0, &child_pid,
1.1       root       74:                "child.exe");
                     75:        printf("exec'd child, pid = %u\n", child_pid);
                     76:        do {
1.1.1.2 ! root       77:                res = DosCWait(1,0, &child_status, &ending_pid, 0);
1.1       root       78:                if (res == 0)
                     79:                        printf("child %u ended\n", ending_pid);
                     80:        } while (res == 0);
                     81: }

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