libexplain/ungetc.c File Reference

#include <libexplain/ac/errno.h>
#include <libexplain/ac/stdio.h>
#include <libexplain/ungetc.h>

Go to the source code of this file.

Functions
const char *	explain_ungetc (int c, FILE *fp)

---

Function Documentation

const char* explain_ungetc	(	int	c,
		FILE *	fp
	)

The explain_ungetc function is used to obtain an explanation of an error returned by the ungetc(3) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.

The errno global variable will be used to obtain the error value to be decoded.

Parameters:

c	The original c, exactly as passed to the ungetc(3) system call.
fp	The original fp, exactly as passed to the ungetc(3) system call.

Returns:

The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.

Note:

This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

Example:

This function is intended to be used in a fashion similar to the following example:

 if (ungetc(c, fp) < 0)
 {
     fprintf(stderr, "%s\n", explain_ungetc(c, fp));
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_ungetc_or_die function.

Definition at line 26 of file ungetc.c.