|explain_ungetc_or_die(3)||Library Functions Manual||explain_ungetc_or_die(3)|
explain_ungetc_or_die - push a character back to a stream and report errors
void explain_ungetc_or_die(int c, FILE *fp);
int explain_ungetc_on_error(int c, FILE *fp);
The explain_ungetc_or_die function is used to call the ungetc(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_ungetc(3) function, and then the process terminates by calling exit(EXIT_FAILURE).
The explain_ungetc_on_error function is used to call the ungetc(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_ungetc(3) function, but still returns to the caller.
The explain_ungetc_or_die function only returns on success, see ungetc(3) for more information. On failure, prints an explanation and exits, it does not return.
The explain_ungetc_on_error function always returns the value return by the wrapped ungetc(3) system call.
The explain_ungetc_or_die function is intended to be used in a fashion similar to the following example:
libexplain version 1.4
Copyright (C) 2010 Peter Miller