对于需要调用C代码的一些小的问题，通常使用Python标准库中的 ctypes 模块就足够了。 要使用 ctypes ，你首先要确保你要访问的C代码已经被编译到和Python解释器兼容 （同样的架构、字大小、编译器等）的某个共享库中。
这里有个c语言读取linux下cpu很memory相关的c代码 ，目的是想要在Python中访问
使用GCC编译成libinfo.so
gcc -fPIC -shared test_cpu_info.c -o libinfo.so
然后就是在Python中加载
import ctypes import os # Try to locate the .so file in the same directory as this file _file = 'libinfo.so' base_dir = os.getcwd() _path =os.path.join(base_dir,_file)#这个路径是so文件的绝对路径 _mod = ctypes.cdll.LoadLibrary(_path) _mem_use_percent = _mod.mem_use_percent _mem_use_percent.argtypes= (ctypes.POINTER(ctypes.c_double),)#这里必须是一个元组序列 否则会报错 def mem_use_percent(): mem_p = ctypes.c_double() _mem_use_percent(mem_p) print(mem_p)
下面是执行这个函数的代码
附上源文件
#include<stdio.h> #include<stdlib.h> #include<string.h> #include <unistd.h> typedef struct MEMPACKED //定义一个mem occupy的结构体 { char name1[20]; //定义一个char类型的数组名name有20个元素 unsigned long MemTotal; char name2[20]; unsigned long MemFree; char name3[20]; unsigned long Buffers; char name4[20]; unsigned long Cached; char name5[20]; unsigned long SwapCached; }MEM_OCCUPY; //proc/stat文件结构 //cpu 633666 46912 249878 176813696 782884 2859 19625 0 //cpu0 633666 46912 249878 176813696 782884 2859 19625 0 //intr 5812844 //ctxt 265816063 //btime 1455203832 //processes 596625 //procs_running 1 //procs_blocked 0 typedef struct CPUPACKED //定义一个cpu occupy的结构体 { char name[20]; //定义一个char类型的数组名name有20个元素 unsigned int user; //定义一个无符号的int类型的user unsigned int nice; //定义一个无符号的int类型的nice unsigned int system;//定义一个无符号的int类型的system unsigned int idle; //定义一个无符号的int类型的idle unsigned int lowait; unsigned int irq; unsigned int softirq; }CPU_OCCUPY; void get_memoccupy(MEM_OCCUPY *mem) //对无类型get函数含有一个形参结构体类弄的指针O { FILE *fd; char buff[256]; MEM_OCCUPY *m; m = mem; fd = fopen("/proc/meminfo", "r"); //MemTotal: 515164 kB //MemFree: 7348 kB //Buffers: 7892 kB //Cached: 241852 kB //SwapCached: 0 kB //从fd文件中读取长度为buff的字符串再存到起始地址为buff这个空间里 fgets(buff, sizeof(buff), fd); sscanf(buff, "%s %lu ", m->name1, &m->MemTotal); fgets(buff, sizeof(buff), fd); sscanf(buff, "%s %lu ", m->name2, &m->MemFree); fgets(buff, sizeof(buff), fd); sscanf(buff, "%s %lu ", m->name3, &m->Buffers); fgets(buff, sizeof(buff), fd); sscanf(buff, "%s %lu ", m->name4, &m->Cached); fgets(buff, sizeof(buff), fd); sscanf(buff, "%s %lu", m->name5, &m->SwapCached); fclose(fd); //关闭文件fd } int get_cpuoccupy(CPU_OCCUPY *cpust) //对无类型get函数含有一个形参结构体类弄的指针O { FILE *fd; char buff[256]; CPU_OCCUPY *cpu_occupy; cpu_occupy = cpust; fd = fopen("/proc/stat", "r"); fgets(buff, sizeof(buff), fd); sscanf(buff, "%s %u %u %u %u %u %u %u", cpu_occupy->name, &cpu_occupy->user, &cpu_occupy->nice, &cpu_occupy->system, &cpu_occupy->idle, &cpu_occupy->lowait, &cpu_occupy->irq, &cpu_occupy->softirq); fclose(fd); return 0; } void cal_cpuoccupy(CPU_OCCUPY *o, CPU_OCCUPY *n,double *result) { unsigned long od, nd; double cpu_use = 0; od = (unsigned long)(o->user + o->nice + o->system + o->idle + o->lowait + o->irq + o->softirq);//第一次(用户+优先级+系统+空闲)的时间再赋给od nd = (unsigned long)(n->user + n->nice + n->system + n->idle + n->lowait + n->irq + n->softirq);//第二次(用户+优先级+系统+空闲)的时间再赋给od double sum = nd - od; double idle = n->idle - o->idle; cpu_use = idle / sum; idle = n->user + n->system + n->nice - o->user - o->system - o->nice; cpu_use = idle / sum; *result = cpu_use; // printf("%.3f\n",cpu_use); } void cpu_use_percent(double*cpu_use) { CPU_OCCUPY cpu_stat1; CPU_OCCUPY cpu_stat2; get_cpuoccupy((CPU_OCCUPY *)&cpu_stat1); usleep(100000); get_cpuoccupy((CPU_OCCUPY *)&cpu_stat2); cal_cpuoccupy((CPU_OCCUPY *)&cpu_stat1, (CPU_OCCUPY *)&cpu_stat2,cpu_use); } void mem_use_percent(double *use) { MEM_OCCUPY mem_stat; get_memoccupy((MEM_OCCUPY *)&mem_stat); *use = mem_stat.MemFree * 1.0 / (mem_stat.MemTotal * 1.0); } int main1( int argc, char **argv ) { MEM_OCCUPY mem_stat; CPU_OCCUPY cpu_stat1; CPU_OCCUPY cpu_stat2; double result; //获取内存 //(MemTotal - MemFree)/ MemTotal get_memoccupy((MEM_OCCUPY *)&mem_stat); //printf(" [MemTotal] = %lu \n [MemFree] = %lu \n [Buffers] = %lu \n [Cached] = %lu \n [SwapCached] = %lu \n", mem_stat.MemTotal, mem_stat.MemFree, mem_stat.Buffers, mem_stat.Cached, mem_stat.SwapCached); printf("%.3f\n", mem_stat.MemFree * 1.0 / ( mem_stat.MemTotal * 1.0 ) ); //第一次获取cpu使用情况 get_cpuoccupy((CPU_OCCUPY *)&cpu_stat1); usleep(100000); //第二次获取cpu使用情况 get_cpuoccupy((CPU_OCCUPY *)&cpu_stat2); //计算cpu使用率 cal_cpuoccupy((CPU_OCCUPY *)&cpu_stat1, (CPU_OCCUPY *)&cpu_stat2,&result); printf("cpu_use:%.3f ",result); return 0; } int main2() { double cpu_use; double mem_use; mem_use_percent(&mem_use); printf("mem_use:%.3f\n",mem_use); cpu_use_percent(&cpu_use); printf("cpu_use:%.3f \n",cpu_use); }
