在centos7 系统编译tengine 时报错：
src/http/ngx_http_upstream_check_module.c:1489:2: error: format ‘%u’ expects argument of type ‘unsigned int’, but argument 3 has type ‘ngx_uint_t’ [-Werror=format=]
count, ngx_http_upstream_check_shm_generation);
^
src/http/ngx_http_upstream_check_module.c:1489:2: error: format ‘%u’ expects argument of type ‘unsigned int’, but argument 4 has type ‘ngx_uint_t’ [-Werror=format=]
src/http/ngx_http_upstream_check_module.c:1492:2: error: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘ngx_uint_t’ [-Werror=format=]
check_len += sprintf(check_status + check_len,"peers->peers.nelts = %d\n", peers->peers.nelts);
^
src/http/ngx_http_upstream_check_module.c:1520:3: error: format ‘%u’ expects argument of type ‘unsigned int’, but argument 4 has type ‘ngx_uint_t’ [-Werror=format=]
peer[i].conf->port);
^
src/http/ngx_http_upstream_check_module.c:1520:3: error: format ‘%u’ expects argument of type ‘unsigned int’, but argument 8 has type ‘ngx_uint_t’ [-Werror=format=]
src/http/ngx_http_upstream_check_module.c:1520:3: error: format ‘%u’ expects argument of type ‘unsigned int’, but argument 9 has type ‘ngx_uint_t’ [-Werror=format=]
src/http/ngx_http_upstream_check_module.c:1520:3: error: format ‘%u’ expects argument of type ‘unsigned int’, but argument 11 has type ‘ngx_uint_t’ [-Werror=format=]
cc1: all warnings being treated as errors
原因很明显，应该是没有添加编译参数，警告被当成了错误处理。
解决办法;
-Wformat=0 就没问题了。Wformat这个配置在Centos下默认是关闭的，所以一直没报错，如果编译的时候打开，也会提示一样的错误。
记录一下另外一个错误：
如果在linux下安装openssl，执行config和make之后，在执行make install时如果出现下面的错误
cms.pod around line 457: Expected text after =item, not a number
cms.pod around line 461: Expected text after =item, not a number
cms.pod around line 465: Expected text after =item, not a number
cms.pod around line 470: Expected text after =item, not a number
cms.pod around line 474: Expected text after =item, not a number
POD document had syntax errors at /usr/bin/pod2man line 69.