current working directory when executing a dll

Question

I run some fortran source code from a C program using a dll. I want to use CALL GETCWD(DIRNAME) in Fortran to access files. Is the Current Working Directory (CWD) the directory where my fortran dll is located or where my C-code is located?

Answer 1

CWD stands for Current Working Directory, and it's (usually) the directory where the current process was launched from. Check [Man7]: GETCWD(3) for more details. I prepared a small example for better understanding what's going on.

code00.c:

#include <errno.h>
#include <stdio.h>
#include <unistd.h>

#define PATH_SIZE 0x0200


int main()
{
    char buf[PATH_SIZE];
    if (getcwd(buf, PATH_SIZE) == NULL) {
        printf("Error %d getting CWD\n", errno);
        return 1;
    }
    printf("CWD: [%s]\n", buf);
    return 0;
}

Output:

[cfati@cfati-5510-0:/mnt/e/Work/Dev/StackOverflow/q054306561]> ~/sopr.sh
### Set shorter prompt to better fit when pasted in StackOverflow (or other) pages ###

[064bit prompt]> ls
code00.c
[064bit prompt]> gcc -o cwd code00.c
[064bit prompt]>
[064bit prompt]> ls
code00.c  cwd
[064bit prompt]> ./cwd
CWD: [/mnt/e/Work/Dev/StackOverflow/q054306561]
[064bit prompt]>
[064bit prompt]> pushd .. && ./q054306561/cwd && popd
/mnt/e/Work/Dev/StackOverflow /mnt/e/Work/Dev/StackOverflow/q054306561
CWD: [/mnt/e/Work/Dev/StackOverflow]
/mnt/e/Work/Dev/StackOverflow/q054306561
[064bit prompt]>
[064bit prompt]> mkdir test && pushd test && ../cwd && popd
/mnt/e/Work/Dev/StackOverflow/q054306561/test /mnt/e/Work/Dev/StackOverflow/q054306561
CWD: [/mnt/e/Work/Dev/StackOverflow/q054306561/test]
/mnt/e/Work/Dev/StackOverflow/q054306561