我写了一个简单的c ++程序test.cpp:
#include <iostream>
#include <string>
using namespace std;
int main() {
string s;
cin >> s;
cout << s << endl;
return 0;
}
为什么runnning gcc test.cpp -o mytest会给我这些错误,还有更多？
Undefined symbols for architecture x86_64:
"std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string()", referenced from:
_main in cc8rGYVq.o
"std::cin", referenced from:
_main in cc8rGYVq.o
下面的第三行返回-1.我该怎么做才能调试？
void *zeroed_block = calloc(512, 1);
lseek(3, sectorNum * 512, SEEK_SET);
return write(fd, zeroed_block, 512); /* This line returns -1 */
当我打印由write(使用perror)引起的错误时原因是"文件描述符错误"
这是我打开文件描述符的代码:
char *diskpath = argv[optind]; – Rose Perrone 1 min ago edit
int fd = diskimg_open(diskpath, (removeFlag == NULL));
int
diskimg_open (char *pathname, int readOnly)
{
return open(pathname, readOnly ? O_RDONLY : O_RDWR);
}
在这三行代码之外,每次使用它时,打开文件描述符的工作都是可靠的.
我在Mac OS上,所以这里是输出dtruss,如所要求的:
SYSCALL(args) = return
open(".\0", 0x0, 0x1) = 3 0
fstat64(0x3, 0x7FFF63557420, 0x0) = 0 0
fcntl(0x3, 0x32, 0x7FFF635576A0) = …当我调用这个构造函数时,为什么我在标题中出现错误？
我打电话User(**args)给以下字典args:
{'name': u'Rose Perrone', 'ipAddress': '127.0.0.1', 'email': u'hi@gmail.com'}
这是构造函数:
def __init__(name,
ipAddress,
password=None,
email=None,
deleted=None,
includePromoted=None,
explicit=None):
我正在尝试拦截此链接上的点击次数:
<a id="test-button" href="#">Test</a>
用这个js:
(function() {
$('#test-button').click(function (event) {
console.log("This code never gets called.")
event.preventDefault();
$('#alert-placeholder').html(['<div class="alert"><a class="close"',
'data-dismiss="alert">×</a>',
'<span>"+message+"</span></div>'].join())
return false;
})
console.log("yes, this code loads");
debugger;
})();
但是URL '#'加载并且click()函数中的代码不会运行.我错过了什么？
我在使用bootstrap的烧瓶应用程序中使用此代码.
我在下面的代码中得到了这个错误,但是当我注释掉最后一行时,错误消失了.最后或倒数第二行有什么问题？
parse error (possibly incorrect indentation or mismatched brackets)
.
-- | Recursively builds the selector
constructSelector :: String -> Selector -> Maybe [String] -> Maybe [String] -> Selector
constructSelector docType selector inputWords tagsSoFar =
case docType of
"tag" -> []
"todo" -> case inputWords of
Nothing -> selector
-- when there are no args left to examine, check if we've
-- recursively accumulated a list of tags
Just ws | ws == [] -> case tagsSoFar of
Nothing -> …我想将PIL图像转换为numpy数组.Numpy的asarray功能只是将图像放在一个0维数组中.
(Pdb) p img
<PIL.Image._ImageCrop image mode=RGB size=1024x0 at 0x106953560>
(Pdb) img.getdata()
<ImagingCore object at 0x104c97b10>
(Pdb) np.asarray(img.getdata())
array([], dtype=float64)
(Pdb) np.asarray(img)
array(<PIL.Image._ImageCrop image mode=RGB size=1024x0 at 0x106953560>, dtype=object)
(Pdb) np.asarray(img).shape
()
(Pdb) np.asarray(img, np.uint8)
*** SystemError: error return without exception set
关于类似SO问题的解决方案不起作用.
我怎样才能加快这个功能？512x512图像需要1.3秒.
def bool_map(image):
'''
Returns an np.array containing booleans,
where True means a pixel has red value > 200.
'''
bool_map = np.zeros(image.shape, dtype=np.bool_)
for row in range(image.shape[0]):
for col in range(image.shape[0]):
if image[row, col, 0] > 200:
bool_map[row, col] = True
return bool_map
我在这个例子中如何滥用gflags？在命令行上设置标志不会覆盖默认值,但是当我根据需要设置标志并且不使用默认值(注释代码)时,它被设置(to False)就好了.
import gflags
from gflags import FLAGS
#gflags.DEFINE_bool('use_cache', None, '')
#gflags.MarkFlagAsRequired('use_cache')
gflags.DEFINE_bool('use_cache', True, '')
if __name__ == '__main__':
if FLAGS.use_cache == True:
print 'use_cache == True'
else:
print 'use_cache == False'
.
~ python testflags.py --use_cache=False
use_cache == True
~ python testflags.py --help
use_cache == True
在我的命令窗口中,我可以执行find([0 1 0]),但是当我在函数中运行find时x = find([0 1 0]),编译器告诉我find没有定义.为什么会这样？
错误是:
??? Error: File: frequentTuples.m Line: 12 Column: 21
"find" previously appeared to be used as a function or command, conflicting with its
use here as the name of a variable.
A possible cause of this error is that you forgot to initialize the
variable, or you have initialized it implicitly using load or eval.
这是代码.错误发生在for循环的第二行.
function [ tuples ] = frequentTuples( k, candidates, transactions, min_support ) …我的.vimrc包含:
set wildmenu " show list instead of just completing
set wildmode=list:longest,full " command <Tab> completion, list matches, then longest common part, then all.
set wildignore+=.cache,.gem,.ivy2,.extras.bash,.themes
set wildignore+=.subversion,.subversion_IDEA
set wildignore+=.Trash
set wildignore+=Desktop,Documents,Downloads
set wildignore+=Library,Movies,Pictures
set wildignore+=spf13vim2
set wildignore+=.CFUserTextEncoding,.DS_Store
set wildignore+=.bash_history,.extra.bash,.irb-history
set wildignore+=.lesshst,.mysql_history,.pry_history
set wildignore+=.reviewboard-cache,.rnd,.sbt.cache.lock
set wildignore+=.scala_history,.sqlite_history,.viminfo
set wildignore+=*.o,*.obj,.git,vendor/rails/**,vendor/gems/**
set wildignore+=*.swp
你可以在这里找到我的完整vimrc .当我在vim中编辑文件时,命中tab产生空格,但没有自动完成.