From 8d1d0ccda9d99994348609d51c03488ae3bddf90 Mon Sep 17 00:00:00 2001
From: rpj <rpj>
Date: Mon, 17 May 2004 04:05:46 +0000
Subject: ''

---
 README.Watcom | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 README.Watcom

(limited to 'README.Watcom')

diff --git a/README.Watcom b/README.Watcom
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+Watcom compiler notes
+=====================
+
+Status
+------
+Not yet usable. Although the library builds under Watcom it
+substantially fails the test suite.
+
+There is a working Wmakefile for wmake for the library build.
+
+invoke as any of:
+wmake -f Wmakefile clean WC
+wmake -f Wmakefile clean WC-inlined
+wmake -f Wmakefile clean WCE
+wmake -f Wmakefile clean WCE-inlined
+
+These build pthreadWC.dll and pthreadWCE.dll.
+
+There is a working Wmakefile for wmake for the test suite.
+
+invoke as any of:
+wmake -f Wmakefile clean WC
+wmake -f Wmakefile clean WCX
+wmake -f Wmakefile clean WCE
+wmake -f Wmakefile clean WC-bench
+wmake -f Wmakefile clean WCX-bench
+wmake -f Wmakefile clean WCE-bench
+
+
+Current known problems
+----------------------
+
+Library build:
+The Watcom compiler uses a different default call convention to MS C or GNU C and so
+applications are not compatible with pthreadVC.dll etc using pre 2003-10-14 versions
+of pthread.h, sched.h, or semaphore.h. The cdecl attribute can be used on exposed
+function prototypes to force compatibility with MS C built DLLs.
+
+However, there appear to be other incompatibilities. Errno.h, for example, defines
+different values for the standard C and POSIX errors to those defined by the MS C
+errno.h. It may be that references to Watcom's threads compatible 'errno' do set
+and return translated numbers consistently, but I have not verified this.
+
+Watcom defines errno as a dereferenced pointer returned by the function
+_get_errno_ptr(). This is similar to both the MS and GNU C environments for
+multithreaded use. However, the Watcom version appears to have a number of problems:
+
+- different threads return the same pointer value. Compare with the MS and GNU C
+versions which correctly return different values (since each thread must maintain
+a thread specific errno value).
+
+- an errno value set within the DLL appears as zero in the application even though
+both share the same thread.
+
+Therefore applications built using the Watcom compiler may need to use
+a Watcom built version of the library (pthreadWC.dll). If this is the case, then
+the cdecl function attribute should not be required.
+
+Application builds:
+The test suite fails with the Watcom compiler.
+
+Test semaphore1.c fails for pthreadWC.dll because errno returns 0 instead of EAGAIN.
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