* Use of typeof
@ 2002-03-01 8:03 Philip Cheng
2002-03-02 11:04 ` Kevin Bailey
0 siblings, 1 reply; 4+ messages in thread
From: Philip Cheng @ 2002-03-01 8:03 UTC (permalink / raw)
To: gcc-help
I would like to use typeof to determine the type of a variable.
However, I keep getting the error when I try to compile the program.
test.c: In function `main':
test.c:8: parse error before "typeof"
Anyone knows how can I solve the problem? Thanks in advance for your help.
Philip
Here is my test program:
#include <stdio.h>
main()
{
double dftest;
dftest = 1.0;
if (__builtin_types_compatible_p (typeof (dftest), double))
printf("It is double\n");
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Use of typeof
2002-03-01 8:03 Use of typeof Philip Cheng
@ 2002-03-02 11:04 ` Kevin Bailey
2002-03-02 13:43 ` Kevin Bailey
2002-03-04 6:36 ` Philip Cheng
0 siblings, 2 replies; 4+ messages in thread
From: Kevin Bailey @ 2002-03-02 11:04 UTC (permalink / raw)
To: gcc-help
There is no such thing as typeof in C.
However, there is in C++ so either rename your file to test.cc
or compile with -xc++.
On Fri, Mar 01, 2002 at 11:01:18AM -0500, Philip Cheng wrote:
> I would like to use typeof to determine the type of a variable.
> However, I keep getting the error when I try to compile the program.
>
> test.c: In function `main':
> test.c:8: parse error before "typeof"
>
> Anyone knows how can I solve the problem? Thanks in advance for your help.
>
> Philip
>
>
> Here is my test program:
>
> #include <stdio.h>
>
> main()
> {
> double dftest;
> dftest = 1.0;
>
> if (__builtin_types_compatible_p (typeof (dftest), double))
> printf("It is double\n");
> }
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Use of typeof
2002-03-02 11:04 ` Kevin Bailey
@ 2002-03-02 13:43 ` Kevin Bailey
2002-03-04 6:36 ` Philip Cheng
1 sibling, 0 replies; 4+ messages in thread
From: Kevin Bailey @ 2002-03-02 13:43 UTC (permalink / raw)
To: gcc-help
Oops, it's typeid, not typeof.
On Sat, Mar 02, 2002 at 11:04:14AM -0800, Kevin Bailey wrote:
> There is no such thing as typeof in C.
>
> However, there is in C++ so either rename your file to test.cc
> or compile with -xc++.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Use of typeof
2002-03-02 11:04 ` Kevin Bailey
2002-03-02 13:43 ` Kevin Bailey
@ 2002-03-04 6:36 ` Philip Cheng
1 sibling, 0 replies; 4+ messages in thread
From: Philip Cheng @ 2002-03-04 6:36 UTC (permalink / raw)
To: Kevin Bailey; +Cc: gcc-help
Kevin:
If you look at
http://gcc.gnu.org/onlinedocs/gcc-3.0.3/gcc_5.html#SEC74
you will find that typeof is gcc extension.
There are two ways of writing the argument to typeof: with an expression
or with a type. Here is an example with an expression:
typeof (x[0](1))
This assumes that x is an array of pointers to functions; the type described
is that of the values of the functions.
Here is an example with a typename as the argument:
typeof (int *)
Seems typeof does not work with the 2nd method. Maybe it is a gcc bug?
Philip
>
> There is no such thing as typeof in C.
>
> However, there is in C++ so either rename your file to test.cc
> or compile with -xc++.
>
> On Fri, Mar 01, 2002 at 11:01:18AM -0500, Philip Cheng wrote:
> > I would like to use typeof to determine the type of a variable.
> > However, I keep getting the error when I try to compile the program.
> >
> > test.c: In function `main':
> > test.c:8: parse error before "typeof"
> >
> > Anyone knows how can I solve the problem? Thanks in advance for your help.
> >
> > Philip
> >
> >
> > Here is my test program:
> >
> > #include <stdio.h>
> >
> > main()
> > {
> > double dftest;
> > dftest = 1.0;
> >
> > if (__builtin_types_compatible_p (typeof (dftest), double))
> > printf("It is double\n");
> > }
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2002-03-02 11:04 ` Kevin Bailey
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2002-03-04 6:36 ` Philip Cheng
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