Getting absolute path of a file

Question

How can I convert a relative path to an absolute path in C on Unix? Is there a convenient system function for this?

On Windows there is a GetFullPathName

Answer 1

There is also a small path library cwalk which works cross-platform. It has cwk_path_get_absolute to do that:

#include 
#include 
#include 
#include 

int main(int argc, char *argv[])
{
  char buffer[FILENAME_MAX];

  cwk_path_get_absolute("/hello/there", "./world", buffer, sizeof(buffer));
  printf("The absolute path is: %s", buffer);

  return EXIT_SUCCESS;
}

Outputs:

The absolute path is: /hello/there/world