android ndk getProperty

ndk_property_get.cpp

// http://stackoverflow.com/questions/26722040/replacement-for-system-property-get-in-android-l-ndk
#include <string>
#include <cstdio>
#include <cstdlib>
#include <errno.h>

int property_get(const char* key, char* out, char* def)
{
  std::string cmd = "getprop ";
  cmd += key;
	FILE* file = popen(cmd.c_str(), "r");
	if(!file) {
		return -1;
	}
	int n = fread(out, 1024, 1, file);
	if(ferror(file)) {
		strcpy(out, def);
		return -2;
	}
	pclose(file);
	return 0;
}

bool getFloatProperty(const char* key, float* pRet)
{
	char str[256] = {0};
	char* endptr = NULL;
	int ret = property_get(key, str, (char*)"");
	if(ret < 0)
		return false;
	errno = 0;
	float val = strtof(str, &endptr);
	if((char*)str==endptr || errno) {
		return false;
	}
	*pRet = val;
	return true;
}