When should I use perror(“…”) and fprintf(stderr, “…”)?

Question

Reading the man pages and some code did not really help me in understanding the difference between - or better, when I should use - perror(\"...\") or fp

Answer 1

perror(const char *s): prints the string you give it followed by a string that describes the current value of errno.

stderr: it's an output stream used to pipe your own error messages to (defaults to the terminal).

Relevant:

char *strerror(int errnum): give it an error number, and it'll return the associated error string.