Created
April 11, 2018 15:39
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concat and remove
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#include <stdio.h> | |
#include <sys/types.h> | |
#include <sys/ipc.h> | |
#include <sys/shm.h> | |
#include <pthread.h> | |
#include <string.h> | |
#include <stdlib.h> | |
// gcc -pthread concat.c -o concat | |
// set pshared for interprocess operation | |
pthread_mutexattr_t attr; | |
int shmid_mutex,shmid_str; | |
key_t key; | |
// shared memory segment for the mutex | |
pthread_mutex_t *shm_mutex; | |
// shared memory for the string | |
char* shm_str; | |
int main(){ | |
pthread_mutexattr_setpshared(&attr,PTHREAD_PROCESS_SHARED); | |
key = 1234; | |
// create shm for mutex | |
if ((shmid_mutex = shmget(key,sizeof(pthread_mutex_t),IPC_CREAT | 0666)) < 0){ | |
perror("Could not create shm for mutex"); | |
exit(1); | |
} | |
if ((shm_mutex = shmat(shmid_mutex,NULL,0)) < 0){ | |
perror("Could not attach shm for mutex"); | |
exit(1); | |
} | |
// initialize the mutex lock to the shared memory segment | |
pthread_mutex_init(shm_mutex,&attr); | |
key = 4567; | |
// create shared memory segment for storing the string | |
if ((shmid_str = shmget(key,sizeof(char)*100,IPC_CREAT | 0666)) < 0){ | |
perror("Could not create shm for string"); | |
exit(1); | |
} | |
if ((shm_str = shmat(shmid_str,NULL,0)) < 0){ | |
perror("Could not attach shm for string"); | |
exit(1); | |
} | |
// initialize the string in shared memory segment | |
strcpy(shm_str,"Model Engineering College"); | |
while(1){ | |
// lock before modifying the string | |
pthread_mutex_lock(shm_mutex); | |
printf("%s\n",shm_str); | |
strcpy(shm_str,"Model Engineering College"); | |
// release the lock after modification | |
pthread_mutex_unlock(shm_mutex); | |
// sleep for 5 secs | |
sleep(5); | |
} | |
return 0; | |
} |
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#include <stdio.h> | |
#include <sys/types.h> | |
#include <sys/ipc.h> | |
#include <sys/shm.h> | |
#include <pthread.h> | |
#include <stdlib.h> | |
int shmid_mutex,shmid_str; | |
key_t key; | |
// shared memory segment for the mutex | |
pthread_mutex_t *shm_mutex; | |
// shared memory for the string | |
char* shm_str; | |
void remove_e(char* str); | |
int main() | |
{ | |
key = 1234; | |
// get the shared memory segment with the mutex lock | |
if ((shmid_mutex = shmget(key,sizeof(pthread_mutex_t),IPC_CREAT | 0666)) < 0){ | |
perror("Could not create shm for mutex"); | |
exit(1); | |
} | |
if ((shm_mutex = shmat(shmid_mutex,NULL,0)) < 0){ | |
perror("Could not attach shm for mutex"); | |
exit(1); | |
} | |
key = 4567; | |
// get the shared memory segment with string | |
if ((shmid_str = shmget(key,sizeof(char)*100,IPC_CREAT | 0666)) < 0){ | |
perror("Could not create shm for string"); | |
exit(1); | |
} | |
if ((shm_str = shmat(shmid_str,NULL,0)) < 0){ | |
perror("Could not attach shm for string"); | |
exit(1); | |
} | |
while(1){ | |
// lock before modifying the string | |
pthread_mutex_lock(shm_mutex); | |
remove_e(shm_str); | |
// release the lock after modification | |
pthread_mutex_unlock(shm_mutex); | |
// sleep for 7 secs | |
sleep(7); | |
} | |
return 0; | |
} | |
void remove_e(char* str){ | |
int i=0; | |
for(i=0;str[i] != '\0';++i){ | |
if(str[i] == 'e' || str[i] == 'E'){ | |
str[i] = '#'; | |
} | |
} | |
} |
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