Question

I am having this code in which I am getting BAD FILE DESCRIPTOR problem at the read system call. However my write call with the same file descriptor is working fine. Please suggest

    void Update_Log( )
{
        struct logDetails update,update1[30];
        struct stat fileData,fileData1;
        int file;
        int index;
        //pthread_t pid;
        char writeBuffer[MAX_BUFFER_SIZE];
        char readBuffer[MAX_BUFFER_SIZE];
        char mBuf[MAX_BUFFER_SIZE],mBuf1[MAX_BUFFER_SIZE];
        if((access("/home/team02/DMS/Server/",F_OK))==0) //checking the file/dir existence
                puts("file found");
        else
                puts("file not found");
        if((file=open("/home/team02/DMS/Server/filename.txt",O_RDONLY|O_WRONLY|O_APPEND,S_IRWXU))==-1)
                perror("file not opened");
        if((fstat(file, &fileData))==-1)
                perror("structure not filled");
        if((stat("/home/team02/DMS/Server/f1",&fileData1))==-1)
                perror("structure not filled");

        //printf("%d/n",fileData.st_mtime);
        //printf("%d",fileData.st_ctime);
        struct tm *mytm = localtime(&fileData.st_mtime);
        struct tm *mytime=localtime(&fileData1.st_mtime);
        strftime(mBuf1,18,"%I:%M:%S-%m%d%y",mytime);
        strftime(mBuf, 18, "%I:%M:%S-%m/%d/%y", mytm);
        puts(mBuf);
        if((strcmp(mBuf,mBuf1)==0))
                puts("equal");
                                else
                puts("not equal");
        strcpy(update.timestamp,mBuf);
        strcpy(update.clientName,mBuf);
        strcpy(update.filename,mBuf1);
        snprintf(writeBuffer,MAX_BUFFER_SIZE,"%s %s %s",update.clientName,update.filename,update.timestamp);
        //printf("%s",writeBuffer);
        //if((pthread_create(&pid,&thread_handler,NULL))!=0)
                //perror("Thread not created");
        if((write(file,writeBuffer,strlen(writeBuffer)))==-1)
                perror("write unsuccessful");
        **if((read(file,readBuffer,MAX_BUFFER_SIZE))==-1)
                perror("read unsuccessful");**
        for(index=0;index<strlen(readBuffer);index++)
        {
                sscanf(readBuffer,"%s %s %s",update1[index].clientName,update1[index].filename,update1[index].timestamp);
                printf("%s",update1[index].clientName);
        }
        close(file);
}

Answer 1

Depending on the run time library, the open mode O_RDONLY|O_WRONLY may be problematic. You probably want O_RDWR to replace that part.

Also, you can get the errno value to find out exactly what the problem is. You are calling perror() in the case of an error. That should be telling you what the issue is. What output does the program generate?