Thanks to Wooble
for pointing it out in the comment section that the problem is due to the working directory. When I launched it through Finder, the current working directory was my home directory.
Below is how I address the problem:
#include <iostream>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <libproc.h>
int main(int argc, char** argv){
// Gets and prints out the current directory
char cwd[1024];
getcwd(cwd, sizeof(cwd));
std::cout << "Current Working Directory: " << cwd << std::endl;
// Above is not necessary
// Changes working directory to directory that contains executable
char pathbuf[PROC_PIDPATHINFO_MAXSIZE];
if(proc_pidpath (getpid(), pathbuf, sizeof(pathbuf)) > 0){ // Gets the executable path
std::string s(pathbuf);
s = s.substr(0,s.find_last_of('/')); // Removes executable name from path
std::cout << "Executable Path: " << s << std::endl;
chdir(s.c_str()); // Changes working directory
}
if(int a = mkdir("abc",0700)){
std::cout << "Failed to create: " << a << std::endl;
}
else{
std::cout << "Created." << std::endl;
}
}