Thread: [C malloc/free] ~ free-ing the allocated memory gives c0000005 Windows error

Originally Posted by Spiegel

The question is: is it just the compiler I'm using, or it's an official C rule, that I cant use "_" for "typedef" names?

No, there is no such rule. However, there are two rules (from C99 Clause 7.1.3 Paragraph 1) that say:

• All identifiers that begin with an underscore and either an uppercase letter or another underscore are always reserved for any use.
• All identifiers that begin with an underscore are always reserved for use as identifiers with file scope in both the ordinary and tag name spaces.

A simple rule of thumb is just to avoid naming things with names that begin with an underscore.

Originally Posted by Spiegel

The name given to this typedef was something like "abc_def" and I was getting an error about something like an "incomplete statement". Banged my head really hard for quite a while, before trying to change the typedef name by taking out the freaking "_". After that, everything worked great.

The thing is, "something like" is not convincing. For example, compile this program:

Code:

#include <stdio.h>

typedef struct X {
    double a;
    int b;
} abc_def;

int main(void)
{
    abc_def x = {1.2, 3};
    printf("%f %d\n", x.a, x.b);
    return 0;
}

What error do you get?

Originally Posted by laserlight

No, there is no such rule. However, there are two rules (from C99 Clause 7.1.3 Paragraph 1) that say:

• All identifiers that begin with an underscore and either an uppercase letter or another underscore are always reserved for any use.
• All identifiers that begin with an underscore are always reserved for use as identifiers with file scope in both the ordinary and tag name spaces.

A simple rule of thumb is just to avoid naming things with names that begin with an underscore.


The thing is, "something like" is not convincing. For example, compile this program:

Code:

#include <stdio.h>

typedef struct X {
    double a;
    int b;
} abc_def;

int main(void)
{
    abc_def x = {1.2, 3};
    printf("%f %d\n", x.a, x.b);
    return 0;
}

What error do you get?

Tried. And gives no error.

I've also tried to write it my way (noobie way) and it still gives no error. I surrender, I dont know why I got the error before but not now. =p
What I know is that the name had a "_" in the middle and stopped giving the error after I took the "_" off.

Code:

#include <stdio.h>

typedef struct X { //YOUR WAY
    double a;
    int b;
} abc_def;

int main(void)
{
    abc_def x = {1.2, 3};
    printf("%f %d\n", x.a, x.b);

    struct y_j //MY WAY
    {
        int a;
        int b;
    };

    typedef struct y_j z_w;

    z_w * a;

    return 0;
}