compatibility with glibc 2.3, warn_unused_result attribute for write()

src/core/nginx.c

diff --git a/src/core/nginx.c b/src/core/nginx.c
index c1c6c0c..0672126 100644
--- a/src/core/nginx.c
+++ b/src/core/nginx.c
@@ -191,6 +191,8 @@
 int ngx_cdecl
 main(int argc, char *const *argv)
 {
+    char             *p;
+    ssize_t           n;
     ngx_int_t         i;
     ngx_log_t        *log;
     ngx_cycle_t      *cycle, init_cycle;
@@ -240,23 +242,30 @@
     }
 
     if (ngx_show_version) {
-        ngx_write_fd(ngx_stderr_fileno, "nginx version: " NGINX_VER CRLF,
-                     sizeof("nginx version: " NGINX_VER CRLF) - 1);
+
+        p = "nginx version: " NGINX_VER CRLF;
+        n = sizeof("nginx version: " NGINX_VER CRLF) - 1;
+
+        if (ngx_write_fd(ngx_stderr_fileno, p, n) != n) {
+            return 1;
+        }
 
         if (ngx_show_configure) {
 #ifdef NGX_COMPILER
-            ngx_write_fd(ngx_stderr_fileno, "built by " NGX_COMPILER CRLF,
-                         sizeof("built by " NGX_COMPILER CRLF) - 1);
+            p = "built by " NGX_COMPILER CRLF;
+            n = sizeof("built by " NGX_COMPILER CRLF) - 1;
+
+            if (ngx_write_fd(ngx_stderr_fileno, p, n) != n) {
+                return 1;
+            }
 #endif
 
-#ifndef __WATCOMC__
+            p = "configure arguments: " NGX_CONFIGURE CRLF;
+            n = sizeof("configure arguments :" NGX_CONFIGURE CRLF) - 1;
 
-            /* OpenWatcomC could not build the long NGX_CONFIGURE string */
-
-            ngx_write_fd(ngx_stderr_fileno,
-                        "configure arguments: " NGX_CONFIGURE CRLF,
-                        sizeof("configure arguments :" NGX_CONFIGURE CRLF) - 1);
-#endif
+            if (ngx_write_fd(ngx_stderr_fileno, p, n) != n) {
+                return 1;
+            }
         }
 
         if (!ngx_test_config) {

src/core/ngx_conf_file.c

diff --git a/src/core/ngx_conf_file.c b/src/core/ngx_conf_file.c
index d968316..31d00de 100644
--- a/src/core/ngx_conf_file.c
+++ b/src/core/ngx_conf_file.c
@@ -912,6 +912,7 @@
 static void
 ngx_conf_flush_files(ngx_cycle_t *cycle)
 {
+    ssize_t           n, len;
     ngx_uint_t        i;
     ngx_list_part_t  *part;
     ngx_open_file_t  *file;
@@ -932,11 +933,24 @@
             i = 0;
         }
 
-        if (file[i].buffer == NULL || file[i].pos - file[i].buffer == 0) {
+        len = file[i].pos - file[i].buffer;
+
+        if (file[i].buffer == NULL || len == 0) {
             continue;
         }
 
-        ngx_write_fd(file[i].fd, file[i].buffer, file[i].pos - file[i].buffer);
+        n = ngx_write_fd(file[i].fd, file[i].buffer, len);
+
+        if (n == NGX_FILE_ERROR) {
+            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
+                          ngx_write_fd_n " to \"%s\" failed",
+                          file[i].name.data);
+
+        } else if (n != len) {
+            ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
+                          ngx_write_fd_n " to \"%s\" was incomplete: %z of %uz",
+                          file[i].name.data, n, len);
+        }
     }
 }
 

src/core/ngx_cycle.c

diff --git a/src/core/ngx_cycle.c b/src/core/ngx_cycle.c
index 39d1e4c..aa0d9ce 100644
--- a/src/core/ngx_cycle.c
+++ b/src/core/ngx_cycle.c
@@ -996,6 +996,7 @@
 void
 ngx_reopen_files(ngx_cycle_t *cycle, ngx_uid_t user)
 {
+    ssize_t           n, len;
     ngx_fd_t          fd;
     ngx_uint_t        i;
     ngx_list_part_t  *part;
@@ -1019,9 +1020,23 @@
             continue;
         }
 
-        if (file[i].buffer && file[i].pos - file[i].buffer != 0) {
-            ngx_write_fd(file[i].fd, file[i].buffer,
-                         file[i].pos - file[i].buffer);
+        len = file[i].pos - file[i].buffer;
+
+        if (file[i].buffer && len != 0) {
+
+            n = ngx_write_fd(file[i].fd, file[i].buffer, len);
+
+            if (n == NGX_FILE_ERROR) {
+                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
+                              ngx_write_fd_n " to \"%s\" failed",
+                              file[i].name.data);
+
+            } else if (n != len) {
+                ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
+                          ngx_write_fd_n " to \"%s\" was incomplete: %z of %uz",
+                          file[i].name.data, n, len);
+            }
+
             file[i].pos = file[i].buffer;
         }
 

src/core/ngx_log.c

diff --git a/src/core/ngx_log.c b/src/core/ngx_log.c
index 1059acf..e3abcd7 100644
--- a/src/core/ngx_log.c
+++ b/src/core/ngx_log.c
@@ -158,7 +158,7 @@
 
     ngx_linefeed(p);
 
-    ngx_write_fd(log->file->fd, errstr, p - errstr);
+    (void) ngx_write_fd(log->file->fd, errstr, p - errstr);
 }
 
 

src/os/unix/ngx_files.h

diff --git a/src/os/unix/ngx_files.h b/src/os/unix/ngx_files.h
index d8182b4..fe14887 100644
--- a/src/os/unix/ngx_files.h
+++ b/src/os/unix/ngx_files.h
@@ -99,7 +99,17 @@
 #define ngx_read_fd              read
 #define ngx_read_fd_n            "read()"
 
-#define ngx_write_fd             write
+/*
+ * we use inlined function instead of simple #define
+ * because glibc 2.3 sets warn_unused_result attribute for write()
+ * and in this case gcc 4.3 ignores (void) cast
+ */
+static ngx_inline ssize_t
+ngx_write_fd(ngx_fd_t fd, void *buf, size_t n)
+{
+    return write(fd, buf, n);
+}
+
 #define ngx_write_fd_n           "write()"
 
 #define ngx_linefeed(p)          *p++ = LF;