我使用以下C代码片段来获取OS X上的CPU负载:
#include <mach/message.h>
#include <mach/mach_host.h>
#include <mach/host_info.h>
[...]
mach_msg_type_number_t count = HOST_CPU_LOAD_INFO_COUNT;
kern_return_t error;
host_cpu_load_info_data_t r_load;
mach_port_t host_port = mach_host_self();
error = host_statistics(host_port, HOST_CPU_LOAD_INFO, (host_info_t)&r_load, &count);
在阅读了cgo教程之后,我尝试将这段代码移植到Go中。得到的代码如下:
package main
/*
#include <stdlib.h>
#include <mach/message.h>
#include <mach/mach_host.h>
#include <mach/host_info.h>
*/
import "C"
func main() {
var err C.kern_return_t
var host_info_out C.host_info_t
var host_port C.mach_port_t = C.mach_host_self()
count := C.mach_msg_type_number_t(C.HOST_CPU_LOAD_INFO_COUNT)
err = C.host_statistics(C.host_t(host_port), C.HOST_CPU_LOAD_INFO, &host_info_out, &count)
}
然而,当我尝试构建代码时,却遇到了以下错误消息。
go build cputimes.go
# command-line-arguments
cputimes.go:33: cannot use &host_info_out (type *_Ctype_host_info_t) as type *_Ctype_integer_t in function argument
我不理解为什么cgo会抱怨类型。 host_statistics()的签名在mach头文件中定义如下:
kern_return_t host_statistics
(
host_t host_priv,
host_flavor_t flavor,
host_info_t host_info_out,
mach_msg_type_number_t *host_info_outCnt
);
var host_info_out
类型从C.host_info_t
更改为C.integer_t
对我有用。 - Kavu