feature_test_macros.7: Update for glibc 2.10 changes to <features.h>

From glibc 2.10, <features.h> understands the values 200809
for _POSIX_C_SOURCE and 700 for _XOPEN_SOURCE, and makes
corresponding changes to defaults for other feature test macros.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man7/feature_test_macros.7

@@ -22,13 +22,7 @@
 .\" Formatted or processed versions of this manual, if unaccompanied by
 .\" the source, must acknowledge the copyright and authors of this work.
 .\"
-.\"
-.\" FIXME .
-.\" Eventually _POSIX_C_SOURCE and _XOPEN_SOURCE entries will need to
-.\" be updated for the next (2008?) POSIX revision.
-.\" The respective values will be 200809 and 700, but as at Feb 2009,
-.\" glibc does not know about these values.
-.TH FEATURE_TEST_MACROS 7 2008-01-02 "Linux" "Linux Programmer's Manual"
+.TH FEATURE_TEST_MACROS 7 2009-04-03 "Linux" "Linux Programmer's Manual"
 .SH NAME
 feature_test_macros \- feature test macros
 .SH SYNOPSIS
@@ -161,6 +155,10 @@ definitions for POSIX.1c (threads).
 (Since glibc 2.3.3)
 The value 200112L or greater exposes definitions corresponding
 to the POSIX.1-2001 base specification (excluding the XSI extension).
+.IP \(bu
+(Since glibc 2.10)
+The value 200809L or greater exposes definitions corresponding
+to the POSIX.1-2008 base specification (excluding the XSI extension).
 .RE
 .TP
 .B _POSIX_SOURCE
@@ -181,6 +179,10 @@ definitions for SUSv2 (UNIX 98).
 (Since glibc 2.2) The value 600 or greater additionally exposes
 definitions for SUSv3 (UNIX 03; i.e., the POSIX.1-2001 base specification
 plus the XSI extension) and C99 definitions.
+.IP \(bu
+(Since glibc 2.10) The value 700 or greater additionally exposes
+definitions for SUSv4 (i.e., the POSIX.1-2008 base specification
+plus the XSI extension).
 .RE
 .TP
 .B _XOPEN_SOURCE_EXTENDED
@@ -268,11 +270,15 @@ Defining this macro (with any value) is equivalent to defining
 .BR _XOPEN_SOURCE_EXTENDED ,
 .BR _POSIX_SOURCE ,
 .B _POSIX_C_SOURCE
-with the value 200112L (199506L in glibc versions before 2.5),
-.\" 199309L in glibc versions before 2.1
+with the value 200809L
+(200112L in glibc versions before 2.10;
+199506L in glibc versions before 2.5;
+199309L in glibc versions before 2.1)
 and
 .B _XOPEN_SOURCE
-with the value 600 (500 in glibc versions before 2.2).
+with the value 700
+(600 in glibc versions before 2.10;
+500 in glibc versions before 2.2).
 In addition, various GNU-specific extensions are also exposed.
 Where standards conflict, BSD definitions are disfavored.
 .TP
@@ -340,9 +346,10 @@ then the following feature test macros are defined by default:
 .BR _SVID_SOURCE ,
 .BR _POSIX_SOURCE ,
 and
-.BR _POSIX_C_SOURCE =200112L
-(199506L in glibc versions before 2.4).
-.\" 199309L in glibc versions before 2.1.
+.BR _POSIX_C_SOURCE =200909L
+(200112L in glibc versions before 2.10;
+199506L in glibc versions before 2.4;
+199309L in glibc versions before 2.1).
 .PP
 If any of
 .BR __STRICT_ANSI__ ,
@@ -390,11 +397,30 @@ if
 is defined with a value greater than or equal to 500 and less than 600;
 or
 .IP \(bu
-200112L (199506L in glibc versions before 2.4),
+(since glibc 2.4) 200112L,
 if
 .B XOPEN_SOURCE
-is undefined, or
-is defined with a value greater than or equal to 600.
+is defined with a value greater than or equal to 600 and less than 700.
+.IP \(bu
+(Since glibc 2.10)
+200809L,
+if
+.B XOPEN_SOURCE
+is defined with a value greater than or equal to 700.
+.IP \(bu
+Older versions of glibc do not know about the values
+2001212L and 200809L for
+.BR _POSIX_C_SOURCE ,
+and the setting of this macro will depend on the glibc version.
+.IP \(bu
+If
+.B _XOPEN_SOURCE
+is undefined, then the setting of 
+.B _POSIX_C_SOURCE
+depends on the glibc version:
+199506L, in glibc versions before 2.4;
+200112L, in glibc 2.4 to 2.9; and
+200809L, since glibc 2.10.
 .RE
 .RE
 .PP