No separate compilation & linking of multithreaded translation units?

Question

Solaris 10 Multithreaded Programming Guide, Chapter 8 (http://docs.sun.com/app/docs/doc/816-5137/compile-94611?a=view) states:
"The Sun Studio C compiler (cc) provides the -mt option to compile and link multithreaded code. The -mt option assures that libraries are linked in appropriate order, and is intended to be used to compile and link in a single step.
If you compile with -mt and link in a separate step, you might get unexpected results. If you compile one translation unit with -mt, you must compile all units of the program with -mt."
The Guide does not provide a way to compile and link in separate steps.
The Guide continues to show how to do Compiling and Linking in the POSIX Threads Environment:
cc -mt [ flag ... ] file... -lpthread [ library... ]
What does this really mean? Does this mean that there is no way to compile a translation unit without linking, and then compile and link all the units to generate an executable? If I want to do the following:
% cc -mt -c file1.c
% cc -mt -c file2.c
% cc -mt main.c file1.o file2.o -lpthreadI would get unexpected results?
Should I do this instead?:
% cc -mt -c file1.c -lpthread
% cc -mt -c file2.c -lpthread
% cc -mt main.c file1.o file2.o -lpthreadIs this what Sun means by "compile and link in a single step"?
Or must I do this?:
% cc -mt main.c file1.c file2.c -lpthreadOn the other hand, note that the Guide also says "If you compile one translation unit with -mt, you must compile all units of the program with -mt." It seems to imply that one can compile a unit without linking. Otherwise it would have said "If you compile and link one translation unit with -mt and -lpthread, you must compile and link all units of the program with -mt and -lpthread." I am confused.
The Sun Studio 12: C User's Guide Appendix B (http://docs.sun.com/app/docs/doc/819-5265/bjapp?a=view) says:
"B.2.46 -mt
Compile and link for multithreaded code.
This option passes -D_REENTRANT to the preprocessor and passes -lthread in the correct order to ld.
The -mt option is required if the application or libraries are multithreaded. ...
Modules that are compiled with -mt must also be linked with -mt. ...
If you compile one translation unit with -mt, compile all units of the program with -mt."
It does not say anything about -mt's compiling and linking in one single step. The words "compiled with -mt must also be linked with -mt" seems to suggest that one can compile and link separately.
The Solaris 9 Multithreaded Programming Guide, Chapter 7 (http://docs.sun.com/app/docs/doc/806-6867/6jfpgdcob?a=view) suggests a different way (not -mt) to compile and link a multithreaded program - using a -D_POSIX_C_SOURCE option. There is no "single step" requirement. Can one still use this approach to compile and link translation units in separate steps?:
% cc -c file1.c -D_POSIX_C_SOURCE=200112L
% cc -c file2.c -D_POSIX_C_SOURCE=200112L
% cc main.c file1.o file2.o -D_POSIX_C_SOURCE=200112L -lpthreadAnd as an aside, I notice that there is a difference between the Solaris 9 Guide and the Solaris 10 Guide on the position of the -lpthread flag in the cc command line. The former, in the "Linking With libthread or libpthread" section, says: "To use libpthread, specify -lpthread before -lc on the ld command line, or last on the cc command line." So I guess if there is a -lm for example, then -lm precedes -lpthread on the cc command line. The latter, as shown in the first paragraph above, suggests that -lpthread precede -lm: cc -mt [ flag ... ] file... -lpthread [ library... ]
I am not sure whether Sun really means that the position of -lpthread should be different between Solaris 9 and 10.

Answer 1

clamage45 wrote:
The C Users Guide and Solaris MT Guide are separately maintained. The part you quote might have been true once long ago, and the material never reviewed.
The C Users Guide is reviewed for every release, and we try to keep it correct and up to date.So, you have some "insider information" because apparently you work for Sun. But this Multithreaded Programming Guide also appears to be revised for every release of the Solaris OS - at least between Sol 9 and Sol 10. As I compared them in my original post, they propose different approaches to compiling a multithreaded program. That is, the Multithreaded Programming Guide was updated for Solaris 10 in this regard. Therefore, it does not appear to me that the Multithreaded Programming Guide is not accurate because it might have never been reviewed and got outdated.