115 lines
4.5 KiB
Plaintext
115 lines
4.5 KiB
Plaintext
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IBM VisualAge C/C++ for OS/2
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============================
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To build Python for OS/2, change into ./os2vacpp and issue an 'NMAKE'
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command. This will build a PYTHON15.DLL containing the set of Python
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modules listed in config.c and a small PYTHON.EXE to start the
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interpreter.
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By changing the C compiler flag /Gd- in the makefile to /Gd+, you can
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reduce the size of these by causing Python to dynamically link to the
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C runtime DLLs instead of including their bulk in your binaries.
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However, this means that any system on which you run Python must have
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the VAC++ compiler installed in order to have those DLLs available.
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During the build process you may see a couple of harmless warnings:
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From the C Compiler, "No function prototype given for XXX", which
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comes from the use of K&R parameters within Python for portability.
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From the ILIB librarian, "Module Not Found (XXX)", which comes
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from its attempt to perform the (-+) operation, which removes and
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then adds a .OBJ to the library. The first time a build is done,
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it obviously cannot remove what is not yet built.
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This build includes support for most Python functionality as well as
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TCP/IP sockets. It omits the Posix ability to 'fork' a process but
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supports threads using OS/2 native capabilities. I have tried to
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support everything possible but here are a few usage notes.
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-- os.popen() Usage Warnings
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With respect to my implementation of popen() under OS/2:
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import os
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fd = os.popen("pkzip.exe -@ junk.zip", 'wb')
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fd.write("file1.txt\n")
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fd.write("file2.txt\n")
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fd.write("file3.txt\n")
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fd.write("\x1a") # Should Not Be Necessary But Is
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fd.close()
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There is a bug, either in the VAC++ compiler or OS/2 itself, where the
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simple closure of the write-side of a pipe -to- a process does not
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send an EOF to that process. I find I must explicitly write a
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control-Z (EOF) before closing the pipe. This is not a problem when
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using popen() in read mode.
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One other slight difference with my popen() is that I return None
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from the close(), instead of the Unix convention of the return code
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of the spawned program. I could find no easy way to do this under
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OS/2.
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-- BEGINLIBPATH/ENDLIBPATH
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With respect to environment variables, this OS/2 port supports the
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special-to-OS/2 magic names of 'BEGINLIBPATH' and 'ENDLIBPATH' to
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control where to load conventional DLLs from. Those names are
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intercepted and converted to calls on the OS/2 kernel APIs and
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are inherited by child processes, whether Python-based or not.
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A few new attributes have been added to the os module:
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os.meminstalled # Count of Bytes of RAM Installed on Machine
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os.memkernel # Count of Bytes of RAM Reserved (Non-Swappable)
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os.memvirtual # Count of Bytes of Virtual RAM Possible
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os.timeslice # Duration of Scheduler Timeslice, in Milliseconds
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os.maxpathlen # Maximum Length of a Path Specification, in chars
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os.maxnamelen # Maximum Length of a Single Dir/File Name, in chars
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os.version # Version of OS/2 Being Run e.g. "4.00"
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os.revision # Revision of OS/2 Being Run (usually zero)
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os.bootdrive # Drive that System Booted From e.g. "C:"
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# (useful to find the CONFIG.SYS used to boot with)
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-- Using Python as the Default OS/2 Batch Language
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Note that OS/2 supports the Unix technique of putting the special
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comment line at the time of scripts e.g. "#!/usr/bin/python" in
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a different syntactic form. To do this, put your script into a file
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with a .CMD extension and added 'extproc' to the top as follows:
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extproc C:\Python\Python.exe -x
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import os
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print "Hello from Python"
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The '-x' option tells Python to skip the first line of the file
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while processing the rest as normal Python source.
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-- Suggested Environment Variable Setup
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With respect to the environment variables for Python, I use the
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following setup:
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Set PYTHONHOME=E:\Tau\Projects\Python;D:\DLLs
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Set PYTHONPATH=.;E:\Tau\Projects\Python\Lib; \
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E:\Tau\Projects\Python\Lib\plat-win
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The EXEC_PREFIX (optional second pathspec on PYTHONHOME) is where
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you put any Python extension DLLs you may create/obtain. There
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are none provided with this release.
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-- Contact Info
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If you have questions, suggestions or problems specifically with
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the OS/2 VAC++ port of Python, please contact me at:
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Jeff Rush <jrush@summit-research.com>.
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I support no other platform but OS/2 (and eventually AmigaDOS).
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