如何在运行时使用C ++获取内存使用情况？
我需要在我的程序运行时获取mem使用VIRT和RES并显示它们。
我到目前为止的尝试：
getrusage（http://linux.die.net/man/2/getrusage）
int who = RUSAGE_SELF;
struct rusage usage;
int ret;
ret=getrusage(who,&usage);
cout<<usage.ru_maxrss;
但我总是得到0。
在Linux上，我从来没有找到ioctl（）解决方案。 对于我们的应用程序，我们根据读取/ proc / pid中的文件编写了一个通用实用程序。 有很多这些文件给出不同的结果。 下面是我们解决的问题（这个问题被标记为C ++，并且我们使用C ++构造来处理I / O，但是如果需要，它应该很容易适应C / I子程序）：
#include <unistd.h>
#include <ios>
#include <iostream>
#include <fstream>
#include <string>
//////////////////////////////////////////////////////////////////////////////
//
// process_mem_usage(double &, double &) - takes two doubles by reference,
// attempts to read the system-dependent data for a process' virtual memory
// size and resident set size, and return the results in KB.
//
// On failure, returns 0.0, 0.0
void process_mem_usage(double& vm_usage, double& resident_set)
{
using std::ios_base;
using std::ifstream;
using std::string;
vm_usage = 0.0;
resident_set = 0.0;
// 'file' stat seems to give the most reliable results
//
ifstream stat_stream("/proc/self/stat",ios_base::in);
// dummy vars for leading entries in stat that we don't care about
//
string pid, comm, state, ppid, pgrp, session, tty_nr;
string tpgid, flags, minflt, cminflt, majflt, cmajflt;
string utime, stime, cutime, cstime, priority, nice;
string O, itrealvalue, starttime;
// the two fields we want
//
unsigned long vsize;
long rss;
stat_stream >> pid >> comm >> state >> ppid >> pgrp >> session >> tty_nr
>> tpgid >> flags >> minflt >> cminflt >> majflt >> cmajflt
>> utime >> stime >> cutime >> cstime >> priority >> nice
>> O >> itrealvalue >> starttime >> vsize >> rss; // don't care about the rest
stat_stream.close();
long page_size_kb = sysconf(_SC_PAGE_SIZE) / 1024; // in case x86-64 is configured to use 2MB pages
vm_usage = vsize / 1024.0;
resident_set = rss * page_size_kb;
}
int main()
{
using std::cout;
using std::endl;
double vm, rss;
process_mem_usage(vm, rss);
cout << "VM: " << vm << "; RSS: " << rss << endl;
}
David Robert Nadeau在他的网站中提供了一个很好的自包含多平台C函数来获取进程驻留集大小（物理内存使用）：
/*
* Author: David Robert Nadeau
* Site: http://NadeauSoftware.com/
* License: Creative Commons Attribution 3.0 Unported License
* http://creativecommons.org/licenses/by/3.0/deed.en_US
*/
#if defined(_WIN32)
#include <windows.h>
#include <psapi.h>
#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
#include <unistd.h>
#include <sys/resource.h>
#if defined(__APPLE__) && defined(__MACH__)
#include <mach/mach.h>
#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
#include <fcntl.h>
#include <procfs.h>
#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
#include <stdio.h>
#endif
#else
#error "Cannot define getPeakRSS( ) or getCurrentRSS( ) for an unknown OS."
#endif
/**
* Returns the peak (maximum so far) resident set size (physical
* memory use) measured in bytes, or zero if the value cannot be
* determined on this OS.
*/
size_t getPeakRSS( )
{
#if defined(_WIN32)
/* Windows -------------------------------------------------- */
PROCESS_MEMORY_COUNTERS info;
GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
return (size_t)info.PeakWorkingSetSize;
#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
/* AIX and Solaris ------------------------------------------ */
struct psinfo psinfo;
int fd = -1;
if ( (fd = open( "/proc/self/psinfo", O_RDONLY )) == -1 )
return (size_t)0L; /* Can't open? */
if ( read( fd, &psinfo, sizeof(psinfo) ) != sizeof(psinfo) )
{
close( fd );
return (size_t)0L; /* Can't read? */
}
close( fd );
return (size_t)(psinfo.pr_rssize * 1024L);
#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
/* BSD, Linux, and OSX -------------------------------------- */
struct rusage rusage;
getrusage( RUSAGE_SELF, &rusage );
#if defined(__APPLE__) && defined(__MACH__)
return (size_t)rusage.ru_maxrss;
#else
return (size_t)(rusage.ru_maxrss * 1024L);
#endif
#else
/* Unknown OS ----------------------------------------------- */
return (size_t)0L; /* Unsupported. */
#endif
}
/**
* Returns the current resident set size (physical memory use) measured
* in bytes, or zero if the value cannot be determined on this OS.
*/
size_t getCurrentRSS( )
{
#if defined(_WIN32)
/* Windows -------------------------------------------------- */
PROCESS_MEMORY_COUNTERS info;
GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
return (size_t)info.WorkingSetSize;
#elif defined(__APPLE__) && defined(__MACH__)
/* OSX ------------------------------------------------------ */
struct mach_task_basic_info info;
mach_msg_type_number_t infoCount = MACH_TASK_BASIC_INFO_COUNT;
if ( task_info( mach_task_self( ), MACH_TASK_BASIC_INFO,
(task_info_t)&info, &infoCount ) != KERN_SUCCESS )
return (size_t)0L; /* Can't access? */
return (size_t)info.resident_size;
#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
/* Linux ---------------------------------------------------- */
long rss = 0L;
FILE* fp = NULL;
if ( (fp = fopen( "/proc/self/statm", "r" )) == NULL )
return (size_t)0L; /* Can't open? */
if ( fscanf( fp, "%*s%ld", &rss ) != 1 )
{
fclose( fp );
return (size_t)0L; /* Can't read? */
}
fclose( fp );
return (size_t)rss * (size_t)sysconf( _SC_PAGESIZE);
#else
/* AIX, BSD, Solaris, and Unknown OS ------------------------ */
return (size_t)0L; /* Unsupported. */
#endif
}
用法
size_t currentSize = getCurrentRSS( );
size_t peakSize = getPeakRSS( );
有关更多讨论，请查看网站，它还提供了获取系统物理内存大小的功能。
旧：
maxrss指出进程的最大可用内存。 0表示对该过程没有限制。 您可能需要的是未ru_idrss数据使用情况ru_idrss 。
新增功能：似乎上述内容实际上并不起作用，因为内核并未填充大部分值。 工作是从proc获取信息。 不是自己解析它，而是使用libproc（procps的一部分）更容易，如下所示：
// getrusage.c
#include <stdio.h>
#include <proc/readproc.h>
int main() {
struct proc_t usage;
look_up_our_self(&usage);
printf("usage: %lun", usage.vsize);
}
编译“ gcc -o getrusage getrusage.c -lproc ”
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