Parse error when including time.h

[aneves]

I have a demo project I'm working on where I've included the time.h standard header. When I build my project, I get the following error:

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In file included from ../src/main.xc:11:
In file included from C:\Program Files (x86)\XMOS\xTIMEcomposer\Community_14.1.0\target/include/xc\time.h:4:
C:\Program Files (x86)\XMOS\xTIMEcomposer\Community_14.1.0\target/include\time.h:47:30: error: parse error before "void"
clock_t    _EXFUN(clock,    (void));
                             ^
C:\Program Files (x86)\XMOS\xTIMEcomposer\Community_14.1.0\target/include\_ansi.h:75:35: note: expanded from macro '_EXFUN'
#define _EXFUN(name, proto)             name proto
                                             ^
xmake[1]: *** [.build_X200/src//main.xc.pca.xml] Error 1
xmake: *** [analyze] Error 2

When I open the time.h header, I see the offending line:

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clock_t	   _EXFUN(clock,    (void));

which after macro expansion becomes a function forward declaration:

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clock_t __clock_t(void);

I can't see why the parser would complain about this. The function name is legal. I've searched all of the other headers in the xTime include folders and __clock_t is not being used or defined anywhere else. I can work around this by commenting that line out since I'm not using that function.

When I compare to time.h headers found on Windows and OS X, the function name is clock as opposed to __clock_t found here.

I know that the clock() function in C just returns the tick count since the program launched. Perhaps XC is attempting to override it since it has it's own set of timer/clock hardware features?

Anyone else experience this issue?

Any insight would be appreciated!

[segher]

Since "clock" is such a common name, it might be defined to something else already.
The error message does not say (does not say much useful at all).

[Folknology]

I (like segher) can definitely recall some naming overlaps between Xmos timer code/headers and some of the standard c header files, however I have not been successful in tracking down any of the relevant Xmos documentation about this.

(Prob worth a quick recursive grep on your XMOSLIBS/target/include/*)

regards
Al

[richard]

<xs1.h> defines a clock type which represents a clock block resource. This clock "type" is actually a macro that expands to __clock_t which recognized as a builtin type by the xC compiler. The C standard library header <time.h> defines the clock() function, as required by the C89 standard. If you include (either directly or indirectly via other header files) <xs1.h> and <time.h> in the same file you get a clash. Normally the macro in the <time.h> header would expand to:

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clock_t clock(void);

However if <xs1.h> is included first then it will expand to:

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clock_t __clock_t(void);

Since __clock_t is a builtin type this is a syntax error, in the same way that trying to declare a function called "int" would result in syntax error.

To avoid this clash you should avoid including both headers in the same file - i.e. try to move the code that uses <time.h> to a separate file that doesn't include <xs1.h>

[segher]

Or include <xs1.h> last, does that work?