Add some documentation for the warn/err functions.

1 files changed, 36 insertions, 12 deletions

diff --git a/apps/systemlib/err.h b/apps/systemlib/err.h
index bc390d233..f798b97e7 100644
--- a/apps/systemlib/err.h
+++ b/apps/systemlib/err.h
@@ -36,6 +36,30 @@
  *
  * Simple error/warning functions, heavily inspired by the BSD functions of
  * the same names.
+ * 
+ * The err() and warn() family of functions display a formatted error
+ * message on the standard error output.  In all cases, the last
+ * component of the program name, a colon character, and a space are
+ * output.  If the fmt argument is not NULL, the printf(3)-like formatted
+ * error message is output.  The output is terminated by a newline
+ * character.
+ * 
+ * The err(), errc(), verr(), verrc(), warn(), warnc(), vwarn(), and
+ * vwarnc() functions append an error message obtained from strerror(3)
+ * based on a supplied error code value or the global variable errno,
+ * preceded by another colon and space unless the fmt argument is NULL.
+ * 
+ * In the case of the errc(), verrc(), warnc(), and vwarnc() functions,
+ * the code argument is used to look up the error message.
+ * 
+ * The err(), verr(), warn(), and vwarn() functions use the global
+ * variable errno to look up the error message.
+ * 
+ * The errx() and warnx() functions do not append an error message.
+ * 
+ * The err(), verr(), errc(), verrc(), errx(), and verrx() functions do
+ * not return, but exit with the value of the argument eval.
+ * 
  */
 
 #ifndef _SYSTEMLIB_ERR_H
@@ -47,18 +71,18 @@ __BEGIN_DECLS
 
 __EXPORT const char *getprogname(void);
 
-__EXPORT void	err(int, const char *, ...) __attribute__((noreturn,format(printf,2, 3)));
-__EXPORT void	verr(int, const char *, va_list) __attribute__((noreturn,format(printf,2, 0)));
-__EXPORT void	errc(int, int, const char *, ...) __attribute__((noreturn,format(printf,3, 4)));
-__EXPORT void	verrc(int, int, const char *, va_list) __attribute__((noreturn,format(printf,3, 0)));
-__EXPORT void	errx(int, const char *, ...) __attribute__((noreturn,format(printf,2, 3)));
-__EXPORT void	verrx(int, const char *, va_list) __attribute__((noreturn,format(printf,2, 0)));
-__EXPORT void	warn(const char *, ...)  __attribute__((format(printf,1, 2)));
-__EXPORT void	vwarn(const char *, va_list)  __attribute__((format(printf,1, 0)));
-__EXPORT void	warnc(int, const char *, ...)  __attribute__((format(printf,2, 3)));
-__EXPORT void	vwarnc(int, const char *, va_list)  __attribute__((format(printf,2, 0)));
-__EXPORT void	warnx(const char *, ...)  __attribute__((format(printf,1, 2)));
-__EXPORT void	vwarnx(const char *, va_list)  __attribute__((format(printf,1, 0)));
+__EXPORT void	err(int eval, const char *fmt, ...)		__attribute__((noreturn,format(printf,2, 3)));
+__EXPORT void	verr(int eval, const char *fmt, va_list)	__attribute__((noreturn,format(printf,2, 0)));
+__EXPORT void	errc(int eval, int code, const char *fmt, ...)	__attribute__((noreturn,format(printf,3, 4)));
+__EXPORT void	verrc(int eval, int code, const char *fmt, va_list) __attribute__((noreturn,format(printf,3, 0)));
+__EXPORT void	errx(int eval, const char *fmt, ...) 		__attribute__((noreturn,format(printf,2, 3)));
+__EXPORT void	verrx(int eval, const char *fmt, va_list)	__attribute__((noreturn,format(printf,2, 0)));
+__EXPORT void	warn(const char *fmt, ...)			__attribute__((format(printf,1, 2)));
+__EXPORT void	vwarn(const char *fmt, va_list)			__attribute__((format(printf,1, 0)));
+__EXPORT void	warnc(int code, const char *fmt, ...)		__attribute__((format(printf,2, 3)));
+__EXPORT void	vwarnc(int code, const char *fmt, va_list)	__attribute__((format(printf,2, 0)));
+__EXPORT void	warnx(const char *fmt, ...)			__attribute__((format(printf,1, 2)));
+__EXPORT void	vwarnx(const char *fmt, va_list)		__attribute__((format(printf,1, 0)));
 
 __END_DECLS