Debug Tracing Options

Windows httpd supports debug tracing to help isolate problems with HTTP, network I/O, and control flow. To enable tracing, include the -x option on the command line. The numeric argument to this option controls which event classes are traced, and can be in decimal or hex (preceded by "0x"). Hex is easier to deal with. The trace classes supported in the current release, and their mask values, are shown below:

  0x00000010    Main dispatcher control flow
  0x00000020    Transaction thread control flow
  0x00000040    Script execution (see note below)
  0x00001000    HTTP protocol, see what your client is doing
  0x00002000    Network I/O and aynchronous event handling
  0x00004000    Network buffer handling, pointers, etc. (verbose)
  0x00040000    Hex/ASCII dump of transmitted packets (verbose)

For example:

  -x0x3030

will trace Main and transaction control flow, HTTP, and Net I/O.

Note on script tracing: When this flag is set, the termporary files used for script execution are not deleted on completion. Also, the DOS virtual machine runs as a normal (open) window instead of an icon, and it stops at the command prompt. This is to allow you to see any spurious output generated by the script before the DOS VM exits. You must type exit at the command prompt to complete execution of the script and return results to the client.

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Robert B. Denny <rdenny@netcom.com>