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Q85498: PRB: /Tp and /Tc Show Unexpected Behavior with Wildcards

Article: Q85498
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,2.0,2.1,4.0,4.1,4.2,5.0
Operating System(s): 
Keyword(s): kbCompiler kbVC100 kbVC150 kbVC200 kbVC210 kbVC400 kbVC410 kbVC420 kbVC500
Last Modified: 14-DEC-2001

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The information in this article applies to:

- Microsoft C/C++ for MS-DOS 
- Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5 
- Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0, 4.1, 4.2, 5.0 
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SYMPTOMS
========

When compiling multiple .CPP or .CXX files using a wildcard syntax and the /Tc
command line option, for example

  cl /Tc *.cpp

the C compiler is invoked only for the first source file matching the wildcard
specification. For all subsequent files, the C++ compiler is invoked. The
inverse is also true. That is, when compiling multiple .C files using a wildcard
syntax and the /Tp command line option, the C++ compiler is invoked only for the
first file; for all subsequent files, the C compiler is invoked.

CAUSE
=====

This behavior is by design. As stated in the online and hard copy documentation
for Microsoft C/C++ version 7.0 and all versions of Microsoft Visual C++ 16- and
32-bit Editions, the following is the correct syntax for the /Tc and /Tp command
line options:

/Tc<filename>   -or-   /Tc <filename>
/Tp<filename>   -or-   /Tp <filename>

Each option refers to only one source file. Therefore, the first file matching
the wildcard specification will be compiled as directed by the corresponding /T?
option. All other files matching the wildcard will be compiled in accordance
with their extension. (The C compiler is invoked for .C files, the C++ compiler
for .CPP or .CXX files.)

MORE INFORMATION
================

The following are two possible workarounds for the potential inconvenience
presented by this behavior:

- Use a makefile to control compilations involving the /Tc or /Tp switch.
  Instead of using wildcards, list the files as dependents of the respective
  .OBJ files. This offers two advantages over using wildcards:

   - Only the files that have changed with respect to their .OBJ are
     recompiled.

   - The proper compiler is invoked for the file to be compiled.

  -or-

- Rename all files in question such that they have the expected extensions. For
  example, rename SRC.CPP to SRC.C if you want the C compiler to be invoked on
  the source.

The sample code below is a makefile that could be used to replace the wildcard
command-line compilation:

Sample Code
-----------

If you wish to compile file1.c, file2.c and file3.c with the C++ compiler and
link them to create exefile.exe, use the following makefile:

  .c.obj:
     cl /c /Tp $<

  exefile.exe : file1.obj file2.obj file3.obj
     link $**, exefile.exe;

Additional query words: 8.00 8.00c 9.00

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Keywords          : kbCompiler kbVC100 kbVC150 kbVC200 kbVC210 kbVC400 kbVC410 kbVC420 kbVC500 
Technology        : kbVCsearch kbVC400 kbAudDeveloper kbZNotKeyword8 kbvc150 kbvc100 kbZNotKeyword3 kbVC410 kbVC420 kbVC500 kbVC200 kbVC210 kbVC32bitSearch kbVC16bitSearch kbVC500Search
Version           : :1.0,1.5,2.0,2.1,4.0,4.1,4.2,5.0
Issue type        : kbprb

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