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Passing Arrays to Functions and Program Compiles with Warnings.

I am trying to compile the following code and I get two warnings. What am I doing wrong?

The code is:

Code:

int sum1;

int sum2;



void thread1(int v[], int v_count) {

sum1 = 0;

int i;

for (i = 0; i < v_count; i++)

sum1 += v[i];

}

void thread2(int v[], int v_count) {

sum2 = 0;

int i;

for (i = 0; i < v_count; i++)

sum2 += v[i];

}





int main ( int argc, char** argv )

{

  int N = 5;

  int i;

  int array1[N];

  for (i =0; i < N; i++) 

  array1[i]= i;

  thread1(array1[i],N);

  thread2(array1[i],N);

    

  return 0;

}

Now when I compile it I get the follwing output; It consists of two warnings:

cc example2.c -o exam -lm -lrt -g
example2.c: In function ‘main’:
example2.c:25: warning: passing argument 1 of ‘thread1’ makes pointer from integer without a cast
example2.c:4: note: expected ‘int *’ but argument is of type ‘int’
example2.c:26: warning: passing argument 1 of ‘thread2’ makes pointer from integer without a cast
example2.c:10: note: expected ‘int *’ but argument is of type ‘int’

The program compiles, but it gives the above warning and it then crashes during execution.

The output is:

./exam
Segmentation fault (core dumped)

Now I believe that these warnings and the program crash are all interconnected and I am not sure what is going on.

I am trying to populate an array, array1[], with integer values and then send it to one of two functions, thread1 or thread2. It does not seem to get there hence the execution crashes.

I just need to know how to fix this program so it runs.

Any help appreciated. Thanks in advance.

Respectfully,

jyunker

Code:

thread1(array1[i],N);

is passing just the value of a single element of the array (and even worse, since i==N at that point it's the content of a memory location one element beyond the end of the array). When you want to reference the whole array, omit the subscript:

Code:

thread1(array1,N);

modifying serial code to run on two cores usig p threads

Now how do I modify the code so thread1 is on one thread (say thread 1) and thread2 is on another thread (say thread 2).

I am using p threads.

Any help appreciated. Thanks in advance.

Respectfully,

jyunker

I would say refer to the manual... the man page on pthread_create.

If it looks anything like mine, there is a complete example included.