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1.1 root 1: Differences Document for the
2: Microsoft (R) CodeView (R) Debugger
3: for Version 2.3
4:
5: (C) Copyright Microsoft Corporation, 1989
6:
7:
8: This file contains release notes for the Microsoft (R) CodeView (R),
9: and notes differences between Version 2.3 and 2.2 of the debugger.
10:
11:
12: ===========================< Contents >==========================
13:
14: This file has two parts.
15:
16: Part Note
17: ---- ----
18: 1 Improved general capabilities of the debugger
19: 2 Debugging child processes
20: 3 Viewing process status
21: 4 Switching to a child processes
22:
23:
24: =========< Part 1: Improved Capabilities of the Debugger >=======
25:
26:
27: While running under Version 2.3 of CodeView the program being debugged
28: has complete access to environment variables, including the PATH
29: variable. Previous versions of CodeView did not guarantee access to the
30: environment.
31:
32: Version 2.3 of CodeView is VIO-window compatible, and can therefore
33: run as a Presentation Manager application under OS/2 systems.
34:
35:
36: ============< Part 2: Debugging Multiple Processes >=============
37:
38:
39: To enable debugging of multiple processes, you must first start up
40: CodeView with the /O (offspring) option. The syntax of this option
41: is simple, as it takes no arguments.
42:
43: If you do not use the /O option, CodeView lets your program spawn new
44: processes, but you will not be able to view or trace through these
45: processes. They run in the background as far as CodeView is concerned.
46:
47: For example, to debug multiple processes of the program SPACEMAN.EXE you
48: would use the following command:
49:
50: CVP /O SPACEMAN
51:
52: The /O option has two limitations:
53:
54: 1. You must have OS/2 Version 1.1 or later to use it.
55:
56: 2. This option is incompatible with the /2 option.
57:
58: The rest of this section assumes that you have successfully started
59: CodeView with the /O option.
60:
61: Every time your program executes a line of code that spawns a child
62: process, CodeView responds by displaying the process ID number (Pid) and
63: asking if you wish to debug the child process. The message displayed is
64: similar to the following:
65:
66: Pid 24 started. Do you wish to debug (y/n)?
67:
68: To debug the child process, type Y and then press ENTER. Type any other
69: letter for no. CodeView takes a different course of action depending on
70: your response:
71:
72: 1. If you respond yes (Y), CodeView spawns a new CodeView process. This
73: process controls execution of your program's child process. Each
74: instance of CodeView spawned in this way becomes a separate debugging
75: session.
76:
77: A new process runs in the same screen group as its parent process
78: (unless you call the DosStartSession system function). Using CodeView
79: does not change this. However, each new instance of CodeView always
80: runs in its own screen group. Since OS/2 supports a maximum of 16
81: screen groups, the number of child processes that you can debug at
82: one time is limited.
83:
84: 2. If you respond no (N), CodeView lets the program spawn the child process.
85: However, you will not be able to control or trace the child process
86: with CodeView. The child process is active but not accessible to
87: CodeView commands.
88:
89: You can move between different CodeView processes in the following two
90: ways: by using the OS/2 Session Manager or the Process command (|). The
91: Process command, in turn, has two forms. You can use this command to
92: view status of child processes or to switch directly to the debugging
93: session of the child process.
94:
95: You may need to make note of process ID numbers when CodeView spawns a
96: process. CodeView identifies multiple processes only by their ID
97: numbers.
98:
99:
100: ==============< Part 3: Viewing Process Status >================
101:
102:
103: To view the status of the child processes (of the current process),
104: enter the Process command followed by no arguments:
105:
106: |
107:
108: CodeView responds by displaying three fields: process ID number, session
109: (screen group) ID number, and yes or no, depending on whether or not
110: each process has its own instance of CodeView. The following example
111: shows a sample process status for a process with three children:
112:
113: 001>|
114: ProcessID SessionID Debugging
115: 00024 00006 Yes
116: 00026 00006 Yes
117: 00028 00006 No
118:
119: In the example above, only processes 24 and 26 can be debugged. Each
120: of these processes corresponds to a different instance of CodeView,
121: and each instance runs in a separate screen group. Process 28 is active
122: but cannot be debugged.
123:
124:
125: ============< Part 4: Debugging Multiple Processes >=============
126:
127:
128: If a child process can be debugged, you can switch to that process
129: directly by using the Process command. Use of this command accomplishes
130: the same end as using the Session Manager but is more direct.
131:
132: To switch to the debugging session for a child process, enter the
133: Process command with the following syntax:
134:
135: | <processID>
136:
137: in which <processID> is the process ID (Pid) of the process you wish to
138: debug.
139:
140: The Process command only works with direct children. In other words, you
141: can spawn a child which in turns spawns another child. The Process
142: command does not give you direct access to the <169>grandchild.<170>
143: Instead, you must switch to the intermediate parent.
144:
145: To return to debugging a parent or grandparent, you must use the OS/2
146: Session Manager.
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