c - strcpy not working with struct member and d_name

Question

Whenever I try to use strcpy on a struct member (which is a static char array) and the d_name attribute of a dirent structure (used for reading a directory), my program doesn't get passed that point. I don't get any errors or warnings, it just doesn't get passed it. The struct is initialized globally.

typedef struct SearchArgs
{
    char inputFile[MAXDIRPATH];
    char word[MAXKEYWORD];
    Buffer * buffer;
}SearchArgs;

SearchArgs * args;//arguments for seachFile

...

dir = opendir(nextItem.path);//opens the next directory

...

dp = readdir(dir);

...

printf("dname: %s\n", dp->d_name);//prints
printf("args->inputFile: %s\n", args->inputFile);//prints
strcpy(args->inputFile, dp->d_name);//not getting passed this point
printf("TEST1\n");//doesn't print

Output:

dname: file2.txt
args->inputFile: (null)

Any insight is much appreciated.

What doesn "not getting passed this point" mean? Does program get terminated with nonzero exit code? — user7771338, Mar 27 '17 at 21:08
@SpencerGoff. You said `args->inputFile` is printed correctly, right? I don't see it in your output. — user7771338, Mar 27 '17 at 21:14
`args->inputFile` is `NULL` so problem is not in posted code. — chux - Reinstate Monica, Mar 27 '17 at 21:17
@SpencerGoff. How do you print `(null)`? Is `args->inputFile == NULL` or is it a string which is literally `"(null)"`? — user7771338, Mar 27 '17 at 21:30
I@FREE_AND_OPEN_SOURCE believe the second. I never touch the value of args->inputFile after defining it in the struct. — Spencer Goff, Mar 27 '17 at 21:36
@SpencerGoff. I am not sure what are you talking about. Can you please post the whole code and the whole output (literally copy all text from console)? I am confused because you said "believe the second" which means `args->inputFile` is string `"(null)"`, but you've said that you didn't touch its value. How is that even possible? — user7771338, Mar 27 '17 at 21:49
Okay, so my code just started working. I believe the problem was that I forgot to allocate space for my struct args, which was fixed with : args = malloc(sizeof(SearchArgs)); — Spencer Goff, Mar 27 '17 at 22:01
@SpencerGoff. Would you like me to post an answer to explain it for future users who may be facing the same problem? — user7771338, Mar 27 '17 at 22:05
@SpencerGoff. Ok, I posted answer. Feel free to accept it :) — user7771338, Mar 27 '17 at 22:57

score 2 · Accepted Answer · answered Mar 27 '17 at 22:57

2

Before using strcpy (and any other opeation with structs or struct properties) it is necesarry to allocate memory space for that struct:

SearchArgs *args = (SearchArgs*)malloc(sizeof(SearchArgs));

answered Mar 27 '17 at 22:57

user7771338

185
6

how would i do this with a list? like `SearchArgs *args[4]` – person the human Jun 20 '20 at 14:02

c - strcpy not working with struct member and d_name

1 Answers1