New, improved, more Posix-compliant strerror_r implementation,

complete with documentation.

Reviewed by:	mike@ gad@
MFC after:	1 week

1 files changed, 19 insertions, 12 deletions

diff --git a/lib/libc/string/strerror.3 b/lib/libc/string/strerror.3
index ed63b25..037b138 100644
--- a/lib/libc/string/strerror.3
+++ b/lib/libc/string/strerror.3
@@ -81,16 +81,7 @@ function renders the same result into
 .Fa strerrbuf
 for a maximum of 
 .Fa buflen
-characters and returns 0 upon success.  If insufficient
-storage is provided in
-.Fa strerrbuf 
-(as specified in 
-.Fa buflen )
-to contain the error string, 
-.Er ERANGE 
-is returned and the string in 
-.Fa strerrbuf
-may not be null-terminated.
+characters and returns 0 upon success.
 .Pp
 The
 .Fn perror
@@ -114,9 +105,25 @@ otherwise, only the error message string is printed.
 If
 .Fa errnum
 is not a recognized error number,
-the error message string will contain
+.Fn strerror
+returns an error message string containing
 .Dq Li "Unknown error:\ "
-followed by the error number in decimal.
+followed by the error number in decimal, while 
+.Fn strerror_r
+returns 
+.Er EINVAL .
+.Pp
+If insufficient storage is provided in
+.Fa strerrbuf 
+(as specified in 
+.Fa buflen )
+to contain the error string, 
+.Fn strerror_r
+returns
+.Er ERANGE 
+and the contents of
+.Fa strerrbuf
+are indeterminate.
 .Pp
 The message strings can be accessed directly using the external
 array