consumer producer code undeclared errors linux debug - c

Question

Trying to compile my code in linux by doing gcc -o consumer.c -lpthread -lm and I am getting compile errors about having undeclared for things I, to the best of my knowledge, have declared. Most of the undeclared seem to be related to buffers, of which this is my first program using buffers. Here are the errors (edited to reflect changes)
typedef char buffer_item buffer[BUFFER_SIZE]; // asm or __attribute__ before "buffer"
both of these(expected ')' before 'item'
int insert_item(buffer_item item)
int insert_item(buffer_item item)
int remove_item(buffer_item *item) //expected ')' before * token
and here is my full code after the changes
#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>
#include <semaphore.h>
#define RAND_DIVISOR 100000000
#define TRUE 1
#define BUFFER_SIZE 1000
pthread_mutex_t mutex; //mutex lock
sem_t full, empty; //semaphores
typedef char buffer_item buffer[BUFFER_SIZE];
int counter; //buffer counter
pthread_t tid1, tid2; //Thread ID
pthread_attr_t attr; // thread attributes
void *producer(void *param); // producer thread
void *consumer(void *param); //consumer thread
void initializeData() {
pthread_mutex_init(&mutex, NULL); //Create mutex lock
sem_init(&full, 0, 0); // Create the full semaphore and initialize to 0
sem_init(&empty, 0, BUFFER_SIZE); // Create the empty semaphore and initialize to BUFFER_SIZE
pthread_attr_init(&attr); //default attributes
counter = 0;
}
// Producer Thread
int insert_item(buffer_item item)
void *producer(void *param) {
while(TRUE) {
// random sleep time
int rNum = rand() / RAND_DIVISOR;
sleep(rNum);
int item = rand()%100; // item is a random number between 1-100
sem_wait(&empty); //get empty lock
pthread_mutex_lock(&mutex); //get mutex lock
if(insert_item(item)) {
fprintf(stderr, " Producer report error condition\n");
}
else {
printf("producer produced %d\n", item);
}
pthread_mutex_unlock(&mutex); //release mutex lock
sem_post(&full); //signal full
}
}
// Consumer Thread
void *consumer(void *param) {
while(TRUE) {
int rNum = rand() / RAND_DIVISOR; // sleep for a random period of time
sleep(rNum);
int item = rand()%100; // item is a random number between 1-100
sem_wait(&full);// aquire the full lock */
pthread_mutex_lock(&mutex);// aquire the mutex lock
if(remove_item(&item)) {
fprintf(stderr, "Consumer report error condition\n");
}
else {
printf("consumer consumed %d\n", item);
}
pthread_mutex_unlock(&mutex);// release mutex lock
sem_post(&empty); //signal empty
}
}
int insert_item(buffer_item item)
{
// add item as long as buffer isn't full
if(counter < BUFFER_SIZE) {
buffer[counter] = item;
counter++;
return 0;
}
else {
return -1; //buffer full error
}
}
// Remove an item from the buffer
int remove_item(buffer_item *item)// remove item and decrement counter when buffer not empty
{
if(counter > 0) {
*item = buffer[(counter-1)];
counter--;
return 0;
}
else { //buffer empty error
}
return -1;
}
int main(int argc, char *argv[]) {
int i; //loop counter
if(argc != 4) {
fprintf(stderr, "USAGE:./main.out <INT> <INT> <INT>\n");
}
int mainSleepTime = atoi(argv[1]); // sleep time in seconds
int numProd = atoi(argv[2]); // producer threads
int numCons = atoi(argv[3]); // consumer threads
initializeData(); //initialize app
for(i = 0; i < numProd; i++) {
pthread_create(&tid1,&attr,producer,NULL);
}
for(i = 0; i < numCons; i++) {
pthread_create(&tid2,&attr,consumer,NULL);
}
// sleep in milliseconds
//sleep(mainSleepTime);
pthread_join(tid1, NULL);
pthread_join(tid2, NULL);
printf("Program Exiting\n");
exit(0);
}
Edit: latest code and screenshot of errors http://tinypic.com/r/xptzww/9
#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>
#include <semaphore.h>
#define RAND_DIVISOR 100000000
#define TRUE 1
#define BUFFER_SIZE 1000
pthread_mutex_t mutex; //mutex lock
sem_t full, empty; //semaphores
typedef char buffer_item;
int counter; //buffer counter
pthread_t tid1, tid2; //Thread ID
pthread_attr_t attr; // thread attributes
void *producer(void *param); // producer thread
void *consumer(void *param); //consumer thread
void initializeData() {
pthread_mutex_init(&mutex, NULL); //Create mutex lock
sem_init(&full, 0, 0); // Create the full semaphore and initialize to 0
sem_init(&empty, 0, BUFFER_SIZE); // Create the empty semaphore and initialize to BUFFER_SIZE
pthread_attr_init(&attr); //default attributes
counter = 0;
}
// Producer Thread
int insert_item(buffer_item item)
void *producer(void *param) {
while(TRUE) {
// random sleep time
int rNum = rand() / RAND_DIVISOR;
sleep(rNum);
int item = rand()%100; // item is a random number between 1-100
sem_wait(&empty); //get empty lock
pthread_mutex_lock(&mutex); //get mutex lock
if(insert_item(item)) {
fprintf(stderr, " Producer report error condition\n");
}
else {
printf("producer produced %d\n", item);
}
pthread_mutex_unlock(&mutex); //release mutex lock
sem_post(&full); //signal full
}
}
// Consumer Thread
void *consumer(void *param) {
while(TRUE) {
int rNum = rand() / RAND_DIVISOR; // sleep for a random period of time
sleep(rNum);
int item = rand()%100; // item is a random number between 1-100
sem_wait(&full);// aquire the full lock */
pthread_mutex_lock(&mutex);// aquire the mutex lock
if(remove_item(&item)) {
fprintf(stderr, "Consumer report error condition\n");
}
else {
printf("consumer consumed %d\n", item);
}
pthread_mutex_unlock(&mutex);// release mutex lock
sem_post(&empty); //signal empty
}
}
int insert_item(buffer_item item){// add item as long as buffer isn't full
if(counter < BUFFER_SIZE) {
buffer[counter] = item;
counter++;
return 0;
}
else {
return -1; //buffer full error
}
}
// Remove an item from the buffer
int remove_item(buffer_item *item)// remove item and decrement counter when buffer not empty
{
if(counter > 0) {
*item = buffer[(counter-1)];
counter--;
return 0;
}
else { //buffer empty error
}
return -1;
}
int main(int argc, char *argv[]) {
int i; //loop counter
if(argc != 4) {
fprintf(stderr, "USAGE:./main.out <INT> <INT> <INT>\n");
}
int mainSleepTime = atoi(argv[1]); // sleep time in seconds
int numProd = atoi(argv[2]); // producer threads
int numCons = atoi(argv[3]); // consumer threads
initializeData(); //initialize app
for(i = 0; i < numProd; i++) {
pthread_create(&tid1,&attr,producer,NULL);
}
for(i = 0; i < numCons; i++) {
pthread_create(&tid2,&attr,consumer,NULL);
}
// sleep in milliseconds
//sleep(mainSleepTime);
pthread_join(tid1, NULL);
pthread_join(tid2, NULL);
printf("Program Exiting\n");
exit(0);
}

Answer 1

You have declared but not defined BUFFER_SIZE.
Instead
char BUFFER_SIZE;
try
char BUFFER_SIZE = some_value;
where some_value should be anything between 1-255
Line:
char buffer_item buffer[BUFFER_SIZE];
should be:
char buffer_item[BUFFER_SIZE];

Answer 2

A variable declaration should look like:
<type name> <variable name>;
There is no standard type buffer_item. If you want to use custom type name it can be defined:
typedef char buffer_item;
I assume that you wanted to use char for that type, since item should keep numbers from 0 to 99 and the char type is enough for that.
After that line the name buffer_item is alias for char. So variables can be declared as buffer_item buffer[BUFFER_SIZE]; or buffer_item item;.
In that case lines like char buffer_item; are redundant. Also you do not need to write char before buffer_item, since buffer_item is already another name for char, so char buffer_item; is the same as char char; that does not make any sense.
Probably that the unknow symbol BUFFER_SIZE should defined as you define #define RAND_DIVISOR 100000000. Typically capital letters in names in C are used for macro definitions. So, you may want to set that size on the top of your file, for example:
#define BUFFER_SIZE 1000
In that case the line char BUFFER_SIZE; is not needed anymore.
You use function insert_item before its declaration. So, to compile that you may put forward declaration also on top before producer():
int insert_item(buffer_item item);
That should be enough to compile the code.
Updated for new errors
Type declaration uses special keyword typedef to create type alias. Here to declare that buffer_item name is used as a type name and it is the same as char it should be exactly:
typedef char buffer_item;
The buffer array should be defined below as:
buffer_item buffer[BUFFER_SIZE];
Forward function declaration requires semicolon at the end:
int insert_item(buffer_item item);
I'm not sure that it will work as expected, but now it should be compiled.