CODEWITHSUNDEEP
cpthreads
Rapidistul
Rapidistul

Reputation: 564

void * typed function parameter

I have a function, void *Client(void *threaData){}

Can you tell me some things about void *threadData parameter. When you use void * parameter and why?

Upvotes: 10

Views: 19238

Answers (2)

haccks
haccks

Reputation: 106012

void * is a generic pointer which can point to any object type. The above function can take a pointer to any type and can return a pointer to any type.

A generic pointer can be used if it is not sure about the data type of data inputted by the user.

Example: The following function will print any data type provided the user input about the type of data

void funct(void *a, int z)
{
    if(z==1)
        printf("%d",*(int*)a); // If user inputs 1, then it means the data is an integer and type  casting is done accordingly.
    else if(z==2)
        printf("%c",*(char*)a); // Typecasting for character pointer.
    else if(z==3)
        printf("%f",*(float*)a); // Typecasting for float pointer
}

Upvotes: 19

Iharob Al Asimi
Iharob Al Asimi

Reputation: 53006

Suppose you want to pass an integer to the void *Client(void *threadData){} function, so you would

int integer;

integer = SOME_VALUE;

Client(&integer);

and in the function

void *Client(void *threadData)
{
    int value;

    value = *(int *)threadData;
}

and since void * can be converted to any pointer type, you can pass any data you need to the Client() function.

Upvotes: 5

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