From 2d05b1c1b4cf51df30903a24d1d7944aa1b8eeb7 Mon Sep 17 00:00:00 2001
From: axel <axel@liljencrantz.se>
Date: Fri, 20 Oct 2006 01:19:47 +1000
Subject: [PATCH] Add compiler warnings for some common incorrect usage of
 functions, such as forgetting to cast null pointers to variadic functions

darcs-hash:20061019151947-ac50b-4043638a7a830fa80fd918f92365f5afe3ff208a.gz
---
 common.h     | 5 +++--
 configure.ac | 9 +++++++++
 env.h        | 4 ++--
 exec.h       | 4 ++--
 expand.h     | 2 +-
 util.h       | 2 +-
 6 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/common.h b/common.h
index d9c7cc274..2cefd584e 100644
--- a/common.h
+++ b/common.h
@@ -106,6 +106,7 @@ extern wchar_t *program_name;
 */
 #define N_(wstr) wstr
 
+
 /**
    Take an array_list_t containing wide strings and converts them to a
    single null-terminated wchar_t **. The array is allocated using
@@ -193,7 +194,7 @@ wchar_t *wcsdupcat( const wchar_t *a, const wchar_t *b );
    Returns a newly allocated concatenation of the specified wide
    character strings. The last argument must be a null pointer.
 */
-wchar_t *wcsdupcat2( const wchar_t *a, ... );
+__sentinel wchar_t *wcsdupcat2( const wchar_t *a, ... );
 
 /**
    Test if the given string is a valid variable name
@@ -256,7 +257,7 @@ const wchar_t *wsetlocale( int category, const wchar_t *locale );
 
    \return zero is needle is not found, of if needle is null, non-zero otherwise
 */
-int contains_str( const wchar_t *needle, ... );
+__sentinel int contains_str( const wchar_t *needle, ... );
 
 /**
    Call read while blocking the SIGCHLD signal. Should only be called
diff --git a/configure.ac b/configure.ac
index 6af096a04..c0699a29f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -92,6 +92,15 @@ AC_SUBST( optbindirs, $optbindirs )
 # Tell autoconf to create config.h header 
 AC_CONFIG_HEADERS(config.h)
 
+AH_BOTTOM([#if __GNUC__ >= 3
+#define __warn_unused __attribute__ ((warn_unused_result))
+#define __sentinel __attribute__ ((sentinel))
+#else
+#define __warn_unused 
+#define __sentinel 
+#endif])
+
+
 # Set up various programs needed for install
 AC_PROG_CC
 AC_PROG_CPP
diff --git a/env.h b/env.h
index ea59ecabf..e192fde49 100644
--- a/env.h
+++ b/env.h
@@ -80,8 +80,8 @@ void env_destroy();
 */
 
 int env_set( const wchar_t *key, 
-			  const wchar_t *val,
-			  int mode );
+			 const wchar_t *val,
+			 int mode );
 
 
 /**
diff --git a/exec.h b/exec.h
index 97345e981..63e0d0a36 100644
--- a/exec.h
+++ b/exec.h
@@ -51,8 +51,8 @@ void exec( job_t *j );
 
   \return the status of the last job to exit, or -1 if en error was encountered.
 */
-int exec_subshell( const wchar_t *cmd, 
-				   array_list_t *l );
+__warn_unused int exec_subshell( const wchar_t *cmd, 
+								 array_list_t *l );
 
 
 /**
diff --git a/expand.h b/expand.h
index 9fb6c240b..7486e9c7b 100644
--- a/expand.h
+++ b/expand.h
@@ -139,7 +139,7 @@ enum
    \param out The list to which the result will be appended.
    \return One of EXPAND_OK, EXPAND_ERROR, EXPAND_WILDCARD_MATCH and EXPAND_WILDCARD_NO_MATCH. EXPAND_WILDCARD_NO_MATCH and EXPAND_WILDCARD_MATCH are normal exit conditions used only on strings containing wildcards to tell if the wildcard produced any matches.
 */
-int expand_string( void *context, wchar_t *in, array_list_t *out, int flag );
+__warn_unused int expand_string( void *context, wchar_t *in, array_list_t *out, int flag );
 
 /**
    expand_one is identical to expand_string, except it will fail if in
diff --git a/util.h b/util.h
index 9f9655085..27f25c0e7 100644
--- a/util.h
+++ b/util.h
@@ -607,7 +607,7 @@ void sb_append_char( string_buffer_t *, wchar_t );
 
    Do not forget to cast the last 0 to (void *), or you might encounter errors on 64-bit platforms!
 */
-void sb_append2( string_buffer_t *, ... );
+__sentinel void sb_append2( string_buffer_t *, ... );
 
 /**
    Append formated string data to the buffer. This function internally