我在一个电机程序（我必须控制多个电机，这就是为什么我使用结构）和我的arduino MEGA一起工作。 当我在驱动功能中使用它作为参数时，我不明白为什么MOTOR超出了范围：
typedef struct motor
{
int EN;
/*some more ints*/
}MOTOR;
MOTOR mot1;
MOTOR mot2; /*this works with no compile error*/
int drive (MOTOR*) /*here i have compile error out of scope, neither with or without pointer*/
{
return 1;
}
void setup()
{}
void loop()
{}
sketch_jul25a:2: error: 'MOTOR' was not declared in this scope
sketch_jul25a:2: error: expected primary-expression before ')' token
sketch_jul25a.ino: In function 'int drive(MOTOR*)':
sketch_jul25a:9: error: 'int drive(MOTOR*)' redeclared as different kind of symbol
sketch_jul25a:2: error: previous declaration of 'int drive'
'MOTOR' was not declared in this scope
答案 0 :(得分：5)
因为走向地狱的道路是出于良好的意图。
Arduino IDE通过在代码开头为所有用户定义的函数生成原型来尝试提供帮助。当其中一个原型引用用户定义的类型时，事情会以所描述的方式爆炸。
诀窍是让IDE无法解析代码：
[0:000> !AnalyzeOOM
---------Heap 11---------
Managed OOM occured after GC #15967 (Requested to allocate 0 bytes)
Reason: Low on memory during GC
Detail: SOH: Failed to reserve memory (16777216 bytes)
---------Heap 20---------
Managed OOM occured after GC #15977 (Requested to allocate 0 bytes)
Reason: Low on memory during GC
Detail: SOH: Failed to reserve memory (16777216 bytes)
---------Heap 21---------
Managed OOM occured after GC #15979 (Requested to allocate 0 bytes)
Reason: Low on memory during GC
Detail: SOH: Failed to reserve memory (16777216 bytes)
---------Heap 22---------
Managed OOM occured after GC #15529 (Requested to allocate 0 bytes)
Reason: Low on memory during GC
Detail: SOH: Failed to reserve memory (16777216 bytes)
---------Heap 23---------
Managed OOM occured after GC #15975 (Requested to allocate 0 bytes)
Reason: Low on memory during GC
Detail: SOH: Failed to reserve memory (16777216 bytes)
---------Heap 25---------
Managed OOM occured after GC #15985 (Requested to allocate 0 bytes)
Reason: Low on memory during GC
Detail: SOH: Failed to reserve memory (16777216 bytes)
---------Heap 27---------
Managed OOM occured after GC #40008 (Requested to allocate 0 bytes)
Reason: Low on memory during GC
Detail: SOH: Failed to reserve memory (16777216 bytes)
---------Heap 30---------
Managed OOM occured after GC #40006 (Requested to allocate 0 bytes)
Reason: Low on memory during GC
Detail: SOH: Failed to reserve memory (16777216 bytes)
0:000> !vmstat
TYPE MINIMUM MAXIMUM AVERAGE BLK COUNT TOTAL
~~~~ ~~~~~~~ ~~~~~~~ ~~~~~~~ ~~~~~~~~~ ~~~~~
Free:
Small 4K 64K 57K 4,651 266,932K
Medium 68K 1,024K 288K 97 27,967K
Large 1,088K 6,080K 2,305K 27 62,247K
Summary 4K 6,080K 74K 4,775 357,150K
Reserve:
Small 4K 64K 12K 926 11,567K
Medium 68K 1,020K 277K 390 108,263K
Large 1,148K 16,376K 12,201K 190 2,318,211K
Summary 4K 16,376K 1,618K 1,506 2,438,043K
Commit:
Small 4K 64K 10K 8,169 85,567K
Medium 68K 1,024K 322K 552 178,023K
Large 1,028K 23,300K 5,137K 221 1,135,447K
Summary 4K 23,300K 156K 8,942 1,399,038K
Private:
Small 4K 64K 11K 5,939 65,578K
Medium 68K 1,024K 311K 472 146,891K
Large 1,028K 23,300K 9,725K 316 3,073,339K
Summary 4K 23,300K 488K 6,727 3,285,811K
Mapped:
Small 4K 64K 11K 85 979K
Medium 68K 1,004K 366K 12 4,399K
Large 1,520K 2,888K 2,206K 4 8,824K
Summary 4K 2,888K 140K 101 14,203K
Image:
Small 4K 64K 9K 3,071 30,575K
Medium 68K 1,024K 294K 458 134,995K
Large 1,032K 15,480K 4,082K 91 371,495K
Summary 4K 15,480K 148K 3,620 537,064K][1]
#############################
0:000> !eeheap -gc
Number of GC Heaps: 32
------------------------------
Heap 0 (1a616d08)
generation 0 starts at 0xa062179c
generation 1 starts at 0xa0621000
generation 2 starts at 0x1ab91000
ephemeral segment allocation context: none
segment begin allocated size
1ab90000 1ab91000 1adce1c8 0x23d1c8(2347464)
a0620000 a0621000 a0867db8 0x246db8(2387384)
Large object heap starts at 0x3ab91000
segment begin allocated size
3ab90000 3ab91000 3b343490 0x7b2490(8070288)
Heap Size: Size: 0xc36410 (12805136) bytes.
------------------------------
Heap 1 (1a619970)
generation 0 starts at 0xa965da00
generation 1 starts at 0xa9621000
generation 2 starts at 0x1bb91000
ephemeral segment allocation context: none
segment begin allocated size
1bb90000 1bb91000 1be9bbd0 0x30abd0(3189712)
a9620000 a9621000 a982dd14 0x20cd14(2149652)
Large object heap starts at 0x3b391000
segment begin allocated size
3b390000 3b391000 3bae09f0 0x74f9f0(7666160)
Heap Size: Size: 0xc672d4 (13005524) bytes.
------------------------------
Heap 2 (1a6215d8)
generation 0 starts at 0xa762370c
generation 1 starts at 0xa7621000
generation 2 starts at 0x1cb91000
ephemeral segment allocation context: none
segment begin allocated size
1cb90000 1cb91000 1d0a4604 0x513604(5322244)
a7620000 a7621000 a78a3a20 0x282a20(2632224)
Large object heap starts at 0x3bb91000
segment begin allocated size
3bb90000 3bb91000 3c384cf8 0x7f3cf8(8338680)
736b0000 736b1000 73769790 0xb8790(755600)
Heap Size: Size: 0x10424ac (17048748) bytes.
------------------------------
Heap 3 (1a624240)
generation 0 starts at 0xb56226d0
generation 1 starts at 0xb5621000
generation 2 starts at 0x1db91000
ephemeral segment allocation context: none
segment begin allocated size
1db90000 1db91000 1debd778 0x32c778(3327864)
b5620000 b5621000 b56346dc 0x136dc(79580)
Large object heap starts at 0x3c391000
segment begin allocated size
3c390000 3c391000 3c88b720 0x4fa720(5220128)
Heap Size: Size: 0x83a574 (8627572) bytes.
------------------------------
Heap 4 (1a626ea8)
generation 0 starts at 0x9762eb1c
generation 1 starts at 0x97621000
generation 2 starts at 0x1eb91000
ephemeral segment allocation context: none
segment begin allocated size
1eb90000 1eb91000 1ee6ae1c 0x2d9e1c(2989596)
97620000 97621000 97a87308 0x466308(4612872)
Large object heap starts at 0x3cb91000
segment begin allocated size
3cb90000 3cb91000 3d36c7b8 0x7db7b8(8239032)
f9e70000 f9e71000 f9e975a0 0x265a0(157088)
Heap Size: Size: 0xf41e7c (15998588) bytes.
------------------------------
Heap 5 (1a639b10)
generation 0 starts at 0x8f62107c
generation 1 starts at 0x8f621000
generation 2 starts at 0x1fb91000
ephemeral segment allocation context: none
segment begin allocated size
1fb90000 1fb91000 20b8500c 0xff400c(16728076)
8f620000 8f621000 8f777088 0x156088(1400968)
Large object heap starts at 0x3d391000
segment begin allocated size
3d390000 3d391000 3d903cb0 0x572cb0(5713072)
Heap Size: Size: 0x16bcd44 (23842116) bytes.
------------------------------
Heap 6 (1a63c778)
generation 0 starts at 0xba6611e8
generation 1 starts at 0xba621000
generation 2 starts at 0x20b91000
ephemeral segment allocation context: none
segment begin allocated size
20b90000 20b91000 20e66118 0x2d5118(2969880)
ba620000 ba621000 ba7051f4 0xe41f4(934388)
Large object heap starts at 0x3db91000
segment begin allocated size
3db90000 3db91000 3e348dd8 0x7b7dd8(8093144)
Heap Size: Size: 0xb710e4 (11997412) bytes.
------------------------------
Heap 7 (1a63f3e0)
generation 0 starts at 0xad621918
generation 1 starts at 0xad621000
generation 2 starts at 0x21b91000
ephemeral segment allocation context: none
segment begin allocated size
21b90000 21b91000 21fe7dd0 0x456dd0(4550096)
ad620000 ad621000 adad37e8 0x4b27e8(4925416)
Large object heap starts at 0x3e391000
segment begin allocated size
3e390000 3e391000 3eaea868 0x759868(7706728)
Heap Size: Size: 0x1062e20 (17182240) bytes.
------------------------------
Heap 8 (1a642048)
generation 0 starts at 0xf5e724e0
generation 1 starts at 0xf5e71000
generation 2 starts at 0x22b91000
ephemeral segment allocation context: none
segment begin allocated size
22b90000 22b91000 22ee2cc8 0x351cc8(3480776)
f5e70000 f5e71000 f5eb04ec 0x3f4ec(259308)
Large object heap starts at 0x3eb91000
segment begin allocated size
3eb90000 3eb91000 3f03b3c0 0x4aa3c0(4891584)
Heap Size: Size: 0x83b574 (8631668) bytes.
------------------------------
Heap 9 (1a648cb0)
generation 0 starts at 0x8d630bc4
generation 1 starts at 0x8d621000
generation 2 starts at 0x23b91000
ephemeral segment allocation context: none
segment begin allocated size
23b90000 23b91000 23e4d69c 0x2bc69c(2868892)
8d620000 8d621000 8daf7fb4 0x4d6fb4(5074868)
Large object heap starts at 0x3f391000
segment begin allocated size
3f390000 3f391000 3f991138 0x600138(6291768)
Heap Size: Size: 0xd93788 (14235528) bytes.
------------------------------
Heap 10 (1a64b918)
generation 0 starts at 0xa86261d0
generation 1 starts at 0xa8621000
generation 2 starts at 0x24b91000
ephemeral segment allocation context: none
segment begin allocated size
24b90000 24b91000 250b5b3c 0x524b3c(5393212)
a8620000 a8621000 a891ad34 0x2f9d34(3120436)
Large object heap starts at 0x3fb91000
segment begin allocated size
3fb90000 3fb91000 3ff89810 0x3f8810(4163600)
Heap Size: Size: 0xc17080 (12677248) bytes.
------------------------------
Heap 11 (1a64e580)
generation 0 starts at 0x916238ec
generation 1 starts at 0x91621000
generation 2 starts at 0x25b91000
ephemeral segment allocation context: none
segment begin allocated size
25b90000 25b91000 25ea5d64 0x314d64(3231076)
91620000 91621000 91930198 0x30f198(3207576)
Large object heap starts at 0x40391000
segment begin allocated size
40390000 40391000 40ac8f50 0x737f50(7569232)
Heap Size: Size: 0xd5be4c (14007884) bytes.
------------------------------
Heap 12 (1a65b850)
generation 0 starts at 0x7c52281c
generation 1 starts at 0x7c521000
generation 2 starts at 0x26b91000
ephemeral segment allocation context: none
segment begin allocated size
26b90000 26b91000 2702cad8 0x49bad8(4831960)
7c520000 7c521000 7c7b662c 0x29562c(2709036)
Large object heap starts at 0x40b91000
segment begin allocated size
40b90000 40b91000 41378c38 0x7e7c38(8289336)
e73d0000 e73d1000 e78cce00 0x4fbe00(5225984)
Heap Size: Size: 0x1414b3c (21056316) bytes.
------------------------------
Heap 13 (1a65ef20)
generation 0 starts at 0xf7e77370
generation 1 starts at 0xf7e71000
generation 2 starts at 0x27b91000
ephemeral segment allocation context: none
segment begin allocated size
27b90000 27b91000 27ee43d4 0x3533d4(3486676)
f7e70000 f7e71000 f828f6fc 0x41e6fc(4318972)
Large object heap starts at 0x41391000
segment begin allocated size
41390000 41391000 41b8edf0 0x7fddf0(8379888)
ebc80000 ebc81000 ec460740 0x7df740(8255296)
7e520000 7e521000 7e56dba8 0x4cba8(314280)
Heap Size: Size: 0x179bba8 (24755112) bytes.
------------------------------
Heap 14 (1a661458)
generation 0 starts at 0x9e65f268
generation 1 starts at 0x9e621000
generation 2 starts at 0x28b91000
ephemeral segment allocation context: none
segment begin allocated size
28b90000 28b91000 28f1aacc 0x389acc(3709644)
9e620000 9e621000 9e96f57c 0x34e57c(3466620)
Large object heap starts at 0x41b91000
segment begin allocated size
41b90000 41b91000 42268f58 0x6d7f58(7176024)
Heap Size: Size: 0xdaffa0 (14352288) bytes.
------------------------------
Heap 15 (1a663990)
generation 0 starts at 0x9faacc7c
generation 1 starts at 0x9faa8ac4
generation 2 starts at 0x29b91000
ephemeral segment allocation context: none
segment begin allocated size
29b90000 29b91000 29cde0e8 0x14d0e8(1364200)
9f620000 9f621000 9fd16c88 0x6f5c88(7298184)
Large object heap starts at 0x42391000
segment begin allocated size
42390000 42391000 42adf6a0 0x74e6a0(7661216)
Heap Size: Size: 0xf91410 (16323600) bytes.
------------------------------
Heap 16 (1a665ec8)
generation 0 starts at 0xc362a47c
generation 1 starts at 0xc3621000
generation 2 starts at 0x2ab91000
ephemeral segment allocation context: none
segment begin allocated size
2ab90000 2ab91000 2afbc464 0x42b464(4371556)
c3620000 c3621000 c3854488 0x233488(2307208)
Large object heap starts at 0x42b91000
segment begin allocated size
42b90000 42b91000 42f635f8 0x3d25f8(4007416)
Heap Size: Size: 0xa30ee4 (10686180) bytes.
------------------------------
Heap 17 (1a668418)
generation 0 starts at 0x94622638
generation 1 starts at 0x94621000
generation 2 starts at 0x2bb91000
ephemeral segment allocation context: none
segment begin allocated size
2bb90000 2bb91000 2bfd1374 0x440374(4457332)
94620000 94621000 948da24c 0x2b924c(2855500)
Large object heap starts at 0x43391000
segment begin allocated size
43390000 43391000 43b7a280 0x7e9280(8295040)
67350000 67351000 6739db20 0x4cb20(314144)
Heap Size: Size: 0xf2f360 (15922016) bytes.
------------------------------
Heap 18 (1a669d20)
generation 0 starts at 0x9a621f68
generation 1 starts at 0x9a621000
generation 2 starts at 0x2cb91000
ephemeral segment allocation context: none
segment begin allocated size
2cb90000 2cb91000 2ce5c30c 0x2cb30c(2929420)
9a620000 9a621000 9a6e597c 0xc497c(805244)
Large object heap starts at 0x43b91000
segment begin allocated size
43b90000 43b91000 43f1f520 0x38e520(3728672)
Heap Size: Size: 0x71e1a8 (7463336) bytes.
------------------------------
Heap 19 (1a66b628)
generation 0 starts at 0x83641300
generation 1 starts at 0x83621000
generation 2 starts at 0x2db91000
ephemeral segment allocation context: none
segment begin allocated size
2db90000 2db91000 2dfaecb8 0x41dcb8(4316344)
83620000 83621000 83855614 0x234614(2311700)
Large object heap starts at 0x44391000
segment begin allocated size
44390000 44391000 44a37488 0x6a6488(6972552)
Heap Size: Size: 0xcf8754 (13600596) bytes.
------------------------------
Heap 20 (1a66cf30)
generation 0 starts at 0x8b621738
generation 1 starts at 0x8b621000
generation 2 starts at 0x2eb91000
ephemeral segment allocation context: none
segment begin allocated size
2eb90000 2eb91000 2ef0c5e4 0x37b5e4(3651044)
8b620000 8b621000 8b94d484 0x32c484(3327108)
Large object heap starts at 0x44b91000
segment begin allocated size
44b90000 44b91000 450100c0 0x47f0c0(4714688)
Heap Size: Size: 0xb26b28 (11692840) bytes.
------------------------------
Heap 21 (1a66e838)
generation 0 starts at 0xf31d3830
generation 1 starts at 0xf31d1000
generation 2 starts at 0x2fb91000
ephemeral segment allocation context: none
segment begin allocated size
2fb90000 2fb91000 2fe8b854 0x2fa854(3123284)
f31d0000 f31d1000 f35a9948 0x3d8948(4032840)
Large object heap starts at 0x45391000
segment begin allocated size
45390000 45391000 458c3008 0x532008(5447688)
Heap Size: Size: 0xc051a4 (12603812) bytes.
------------------------------
Heap 22 (1a670140)
generation 0 starts at 0x9867de74
generation 1 starts at 0x98621000
generation 2 starts at 0x30b91000
ephemeral segment allocation context: none
segment begin allocated size
30b90000 30b91000 3102bbdc 0x49abdc(4828124)
98620000 98621000 988edc84 0x2ccc84(2935940)
Large object heap starts at 0x45b91000
segment begin allocated size
45b90000 45b91000 462adab8 0x71cab8(7457464)
Heap Size: Size: 0xe84318 (15221528) bytes.
------------------------------
Heap 23 (1a671a48)
generation 0 starts at 0xe8c810dc
generation 1 starts at 0xe8c81000
generation 2 starts at 0x31b91000
ephemeral segment allocation context: none
segment begin allocated size
31b90000 31b91000 31de8af0 0x257af0(2456304)
e8c80000 e8c81000 e8f756f8 0x2f46f8(3098360)
Large object heap starts at 0x46391000
segment begin allocated size
46390000 46391000 467d71b0 0x4461b0(4481456)
Heap Size: Size: 0x992398 (10036120) bytes.
------------------------------
Heap 24 (1a673350)
generation 0 starts at 0xa1621544
generation 1 starts at 0xa1621000
generation 2 starts at 0x32b91000
ephemeral segment allocation context: none
segment begin allocated size
32b90000 32b91000 32f74f04 0x3e3f04(4079364)
a1620000 a1621000 a1803858 0x1e2858(1976408)
Large object heap starts at 0x46b91000
segment begin allocated size
46b90000 46b91000 4737fc08 0x7eec08(8317960)
67b90000 67b91000 67d11100 0x180100(1573120)
Heap Size: Size: 0xf35464 (15946852) bytes.
------------------------------
Heap 25 (1a674c58)
generation 0 starts at 0x8c6222b8
generation 1 starts at 0x8c621000
generation 2 starts at 0x33b91000
ephemeral segment allocation context: none
segment begin allocated size
33b90000 33b91000 33edff20 0x34ef20(3469088)
8c620000 8c621000 8ca2c690 0x40b690(4241040)
Large object heap starts at 0x47391000
segment begin allocated size
47390000 47391000 47a011a0 0x6701a0(6750624)
Heap Size: Size: 0xdca750 (14460752) bytes.
------------------------------
Heap 26 (1a676560)
generation 0 starts at 0x9b62150c
generation 1 starts at 0x9b621000
generation 2 starts at 0x34b91000
ephemeral segment allocation context: none
segment begin allocated size
34b90000 34b91000 34fa6200 0x415200(4280832)
9b620000 9b621000 9b8b531c 0x29431c(2704156)
Large object heap starts at 0x47b91000
segment begin allocated size
47b90000 47b91000 48373ec0 0x7e2ec0(8269504)
7aa10000 7aa11000 7ab44168 0x133168(1257832)
Heap Size: Size: 0xfbf544 (16512324) bytes.
------------------------------
Heap 27 (1a677e68)
generation 0 starts at 0x92630b90
generation 1 starts at 0x92621000
generation 2 starts at 0x35b91000
ephemeral segment allocation context: none
segment begin allocated size
35b90000 35b91000 361323f0 0x5a13f0(5903344)
92620000 92621000 929fcd4c 0x3dbd4c(4046156)
Large object heap starts at 0x48391000
segment begin allocated size
48390000 48391000 48b76c48 0x7e5c48(8281160)
f0680000 f0681000 f06f4570 0x73570(472432)
Heap Size: Size: 0x11d62f4 (18703092) bytes.
------------------------------
Heap 28 (1a679770)
generation 0 starts at 0xe1c610dc
generation 1 starts at 0xe1c61000
generation 2 starts at 0x36b91000
ephemeral segment allocation context: none
segment begin allocated size
36b90000 36b91000 37076c64 0x4e5c64(5135460)
e1c60000 e1c61000 e1ed5044 0x274044(2572356)
Large object heap starts at 0x48b91000
segment begin allocated size
48b90000 48b91000 4937c3a8 0x7eb3a8(8303528)
f51d0000 f51d1000 f56afdf8 0x4dedf8(5107192)
Heap Size: Size: 0x1423e48 (21118536) bytes.
------------------------------
Heap 29 (1a67b078)
generation 0 starts at 0xa6621380
generation 1 starts at 0xa6621000
generation 2 starts at 0x37b91000
ephemeral segment allocation context: none
segment begin allocated size
37b90000 37b91000 37ecffc0 0x33efc0(3403712)
a6620000 a6621000 a6873190 0x252190(2433424)
Large object heap starts at 0x49391000
segment begin allocated size
49390000 49391000 49a365c8 0x6a55c8(6968776)
Heap Size: Size: 0xc36718 (12805912) bytes.
------------------------------
Heap 30 (1a67c980)
generation 0 starts at 0xb36238ac
generation 1 starts at 0xb3621000
generation 2 starts at 0x38b91000
ephemeral segment allocation context: none
segment begin allocated size
38b90000 38b91000 38eda4b8 0x3494b8(3445944)
b3620000 b3621000 b36978b8 0x768b8(485560)
Large object heap starts at 0x49b91000
segment begin allocated size
49b90000 49b91000 49ffd360 0x46c360(4637536)
Heap Size: Size: 0x82c0d0 (8569040) bytes.
------------------------------
Heap 31 (1a67e288)
generation 0 starts at 0x79a11784
generation 1 starts at 0x79a11000
generation 2 starts at 0x39b91000
ephemeral segment allocation context: none
segment begin allocated size
39b90000 39b91000 3a35caf0 0x7cbaf0(8174320)
79a10000 79a11000 79ec789c 0x4b689c(4941980)
Large object heap starts at 0x4a391000
segment begin allocated size
4a390000 4a391000 4a94e330 0x5bd330(6017840)
Heap Size: Size: 0x123f6bc (19134140) bytes.
------------------------------
GC Heap Size: Size: 0x1c1341b8 (471024056) bytes.
IDE运行到namespace
{
int drive (MOTOR*)
{
return 1;
}
}
并且不知道如何处理后面的块，所以跳过它。
答案 1 :(得分：1)
我建议这应该和命名空间选项一样好吗？
struct motor
{
int EN;
/*some more ints*/
};
int drive (motor* mtr);
motor mot1;
motor mot2; /*this works with no compile error*/
int drive (motor* mtr)
{
return 1;
}
void setup()
{}
void loop()
{
int a = drive(&mot1);
}
答案 2 :(得分：0)
编辑：我的原始答案做了一些假设，即Arduino IDE比实际更接近AVR-GCC。对于那些熟悉C或C ++并且正在使用这些芯片做大量工作的人的一般建议是直接使用Atmel studio和AVR-GCC，因为这样会遇到更少的问题。
Arduino实际上是C ++，但在将代码转换为为芯片编译的C ++代码之前，它会进行一些预处理（比如从main和setup创建loop）。您遇到的问题是由于预处理步骤而导致Ignacio Vazquez-Abrams' answer解释。
作为更通用的c ++用法说明，我建议将结构定义更改为：
struct motor
{
int EN;
/*some more ints*/
};
您可能需要阅读Difference between 'struct' and 'typedef struct' in C++?以了解为什么c ++中的内容会有所不同。