Structures and arrays

[GoogleCodeExporter]

What steps will reproduce the problem?
1.Execute code:
struct TestStruct
{
int b;
};
typedef struct TestStruct TestStruct;

TestStruct*structs=malloc(sizeof(TestStruct)*200);
for(int i=0;i<200;i++)
    {
    structs[i].b=1;
    }


I get the error:
structs[i].b=65;
tempCode.c:16: can't use '.' on something that's not a struct or union:it's a 
int

Original issue reported on code.google.com by [email protected] on 13 Aug 2010 at 7:37

[GoogleCodeExporter]

What is the expected result and where does this error occur in the code?

Original comment by [email protected] on 15 Dec 2010 at 10:01

[GoogleCodeExporter]

THE CORRECT FORM IS:
//-----------------------------------------------------
#define SIZE 200

typedef struct TestStruct TestStruct;

struct TestStruct
{
  int b;
};

TestStruct **structs = (TestStruct**)malloc( sizeof(TestStruct*) * SIZE );

// SET ALL NULL
for(int i=0;i<SIZE;i++)
  structs[i] = NULL;

for(int i=0;i<SIZE;i++)
    {
          structs[i] = malloc( sizeof(TestStruct) );
          structs[i].b = 1;
    }

//-----------------------------------------------------

gokernel
[email protected]

Original comment by [email protected] on 16 Dec 2010 at 12:52

[GoogleCodeExporter]

This seems to be a bug in expression parsing. The [] and . operators have equal 
operator precedence. This is leading to right-to-left evaluation by default, 
which is incorrect - it should be left-to-right for these operators.

I'm still thinking about how to fix this.

Original comment by [email protected] on 7 Jan 2011 at 4:29

• Changed state: Started

[GoogleCodeExporter]

Turns out it was because the expression stack wasn't being collapsed on a 
closing square bracket.

Original comment by [email protected] on 14 Feb 2011 at 4:05

[GoogleCodeExporter]

Fixed in revision r520

Original comment by [email protected] on 14 Feb 2011 at 6:06

[GoogleCodeExporter]

Verified

Original comment by [email protected] on 14 Feb 2011 at 6:06

• Changed state: Verified