warning: comparison between pointer and integer in C

Question

I get a warning

warning: comparison between pointer and integer

on the line containing if from the next piece of code:

Answer 1

The prototype of getcwd is

char *getcwd(char *buf, size_t size);

Make sure you include <unistd.h> otherwise the return type would default to int.

Here, even Ideone gives its Current Working Directory

Answer 2

have you included the .h necessary so that the compiler understands what getcwd returns?

the behavior of your c compilers is probably to assume an int return value from every undefined function.

Answer 3

Modify line with this one if (getcwd(cwd, sizeof(cwd)) != NULL)

Answer 4

Do you include unistd.h? If not, the error appears because your C compiler is assuming getcwd returns int.

The fix? Include unistd.h

Answer 5

In the return types section of the following link, getcwd returns null on failure. Thus, instead of checking for != (char *)NULL just check for != NULL

http://linux.die.net/man/3/getcwd