string concatenation using #define in C

Question

I am trying to concatenate strings and 2/3 strings are paths and are defined in #define

For example:

#define BASE_PATH "foo/bar"
#define BIN_PATH "baz/bin"

I want to be able to direct to the predefined paths. An example use case would be viewing the contents of that folder.

char path_of_executable[256];
printf ("%s \n",executable);
snprintf(path_of_executable, sizeof 256, "%s,%s,%s",BASE_PATH,executable,BIN_PATH);
printf("%s \n",path_of_executable);
chdir(path_of_executable);
execlp("ls","ls","-l",NULL);

The path_of_executable is printed out as /fo

I am not able to direct to that path but instead the files in the current folder are printed out. Any idea what could be the problem?

score 2 · Accepted Answer · answered Jul 09 '13 at 15:21

2

You're using sizeof 256, which translates to sizeof int, which apparently 4 on your platform. That's why the resulting string doesn't exceed 4 characters (including the null-terminator). Use sizeof path_of_executable instead.

answered Jul 09 '13 at 15:21

Kninnug

7,902
1
29
41

Woha!. But why can't I change to that directory? . I take back my question – pistal Jul 09 '13 at 15:23
The additional `,` between `%s` created the problem. – pistal Jul 09 '13 at 15:24

score 2 · Answer 2 · answered Jul 09 '13 at 15:21

2

Replace sizeof 256 with sizeof( path_of_executable )

answered Jul 09 '13 at 15:21

Curt

5,328
1
20
34

score 1 · Answer 3 · answered Jul 09 '13 at 15:21

1

In the line

snprintf(path_of_executable, sizeof 256, "%s,%s,%s",BASE_PATH,executable,BIN_PATH);

replace sizeof 256 with sizeof(path_of_executable)

answered Jul 09 '13 at 15:21

Jimbo

4,222
3
24
44

string concatenation using #define in C

3 Answers3