Here is my code of trying to open a file-descriptor and write data to it.
Now If I don't give any CL argument, then the response isCode:#include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <string.h> #include <sys/stat.h> #include <unistd.h> void usage(char *prog_name,char *filename) { printf("Usage: %s <data to add to %s>\n", prog_name, filename); exit(0); } void fatal(char *); void *ec_malloc(unsigned int); int main(int argc,char *argv[]) { int fd; char *buffer,*datafile; buffer = (char*)ec_malloc(100); datafile = (char*)ec_malloc(20); strcpy(datafile,"/home/note"); if(argc<2) usage(argv[0],datafile); strcpy(buffer,argv[1]); printf("[DEBUG] buffer@ %p: \'%s\'\n", buffer, buffer); printf("[DEBUG] datafile @ %p: \'%s\'\n", datafile, datafile); strncat(buffer,"\n",1); fd = open(datafile,O_WRONLY|O_CREAT|O_APPEND,S_IRUSR|S_IWUSR); if(fd = -1) fatal("In main() while opening file\n"); printf("[DEBUG] file descriptor is %d\n", fd); if(write(fd, buffer, strlen(buffer)) == -1) fatal("in main() while writing buffer to file"); if(close(fd) == -1) fatal("in main() while closing file"); printf("Note has been saved.\n"); free(buffer); free(datafile); } void fatal(char *message){ char error_message[100]; strcpy(error_message,"[!!] Fatal Error "); strncat(error_message,message,strlen(message)); perror(error_message); exit(-1); } void *ec_malloc(unsigned int x){ void *ptr = malloc(x); if(ptr == NULL) fatal("in ec_malloc() on memory allocation"); return ptr; }
But if I give command line such as, `./simplenote "This is a test"` than no filedescriptor is returned. Here is the output of what I get,Code:Usage: ./simplenote <data to add to /tmp/note>
So, What is the problem? Why can't it open the file?Code:[DEBUG] buffer@ 0x1edf010: 'this is a test note' [DEBUG] datafile @ 0x1edf080: '/tmp/note' [!!] Fatal Error In main() while opening file : Success
