I can't find this covered in the FAQ:
typedef int foo;
typedef struct foo
{
int a, b, c;
} bar;
int main()
{
struct foo f1;
foo f2;
return 0;
}
it compiles with just a warning about unused variables f1, f2
but this seems ambiguous to me. What type is "foo" - is it
an "int", or a "struct" ?
how should a compiler treat this type "foo"??
thanks,
James 4 1473
James Brown wrote: I can't find this covered in the FAQ:
typedef int foo;
typedef struct foo { int a, b, c;
} bar;
int main() { struct foo f1; foo f2; return 0; }
it compiles with just a warning about unused variables f1, f2
but this seems ambiguous to me. What type is "foo" - is it an "int", or a "struct" ?
how should a compiler treat this type "foo"??
thanks, James
"foo" is an int
"struct foo" is a struct
Tags of structures, unions and enumerations belong to one namespace,
ordinary identifiers to another. See paragraph 6.2.3 of the 'C' standard.
Robert
James Brown wrote: I can't find this covered in the FAQ:
typedef int foo;
typedef struct foo { int a, b, c;
} bar;
int main() { struct foo f1; foo f2; return 0; }
it compiles with just a warning about unused variables f1, f2
but this seems ambiguous to me. What type is "foo" - is it an "int", or a "struct" ?
Given..
typedef int foo;
foo is now an synonym for int.
Given struct foo, foo is a tag and does not conflict with the typedef of
the same name.
But struct foo is synonymous with bar. Regard..
#include <stdio.h>
typedef int foo;
typedef struct foo {
int a, b, c;
} bar;
int main(void) {
bar f0;
struct foo f1;
foo f2;
f2 = 42;
f0.a = f2;
f1.a = f2;
printf("%d %d %d\n", f2, f0.a, f1.a);
return 0;
}
how should a compiler treat this type "foo"??
thanks, James
--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---
"James Brown" <dont_bother> writes: I can't find this covered in the FAQ:
typedef int foo;
typedef struct foo { int a, b, c;
} bar;
int main() { struct foo f1; foo f2; return 0; }
it compiles with just a warning about unused variables f1, f2
but this seems ambiguous to me. What type is "foo" - is it an "int", or a "struct" ?
how should a compiler treat this type "foo"??
As others have pointed out, there is no ambiguity.
<OT>
You may be confusing this with C++. In C++, the "struct foo"
declaration allows you to refer to the type as either "struct foo" or
"foo". This may create an ambiguity; comp.lang.c++ (or a C++
textbook, or the C++ standard, or your C++ compiler if it's
conforming) would be the place to ask how it's resolved.
</OT>
--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.
"James Brown" <dont_bother> wrote in message
news:vv********************@pipex.net... I can't find this covered in the FAQ:
typedef int foo;
typedef struct foo { int a, b, c;
} bar;
int main() { struct foo f1; foo f2; return 0; }
it compiles with just a warning about unused variables f1, f2
but this seems ambiguous to me. What type is "foo" - is it an "int", or a "struct" ?
how should a compiler treat this type "foo"??
thanks, James
thanks for the replies, I hadn't appreciated that there was a
separate namespace for structure-tags
James This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics
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