File exists, but open file still always returns -1

Question

File \"~/workspace/Test.txt\" does exist, but fd always returns -1. Can somebody please give a hint as to what is wrong with the code? Thanks.

 int fd = open(\"~         


        

Answer 1

(Assuming your OS is some Posix like Linux)

The ~ should be expanded. Usually the shell expands it. But open wants a real file path.

You could try:

std::string fname (getenv("HOME"));
fname += "/workspace/Test.txt";
int fd = open(fname.c_str(), O_RDONLY);
if (fd<0) {
   std::cerr << "failed to open " << fname 
             << " : " << strerror(errno) << std::endl;
   return false;
}   

See glob(7), wordexp(3), getenv(3), strerror(3), open(2), environ(7)

Read Advanced Linux Programming