EXAMPLES:
undef $foo;
my $bar = undef;
SEE ALSO:
perldoc -f undef
Questions tagged [undef]
57 questions
0
votes
1 answer
#undef seems to have no effect on macro redefinitions (warning C4005)
Trying to fix the following "macro redefinition" warning:
1>Path\to\MKL\include\math.h(1577): warning C4005: 'HUGE_VALF' : macro redefinition
1> Path\to\Microsoft Visual Studio 12.0\VC\include\../../vc/include/math.h(104) : see previous…
Pietro
- 12,086
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0
votes
0 answers
C++: Check / Assert a defined constant at its redefinition
I am currently trying to use two headers defining (partially) the same constants. Typically the constants should be the same but my plan is to add a check to be absolutely sure. The problem can be described by the following minimal example:
#include…
Fruchtzwerg
- 10,999
- 12
- 40
- 49
0
votes
1 answer
DolphinDB throws an exception when reassigning an undef-ed variable
In DolphinDB, I defined an variable, called the undef function to undefine it, and reassigned a vector to it. But my code threw an exception which I could not understand.
To simplify the problem, I will provide a minimal example that throws the…
Clyx
- 43
- 7
0
votes
1 answer
#undef main gives no result
I'm working with MVisualC++ 2010 and when I try to undefine the "main", there's no result and the console launches as usual. I was expecting some missing entry point error or something.
Why is that?
#undef main
int main()
{
}
Neomex
- 1,650
- 6
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- 38
0
votes
1 answer
Remove null fields in JSON String in Perl
I am modifying a Perl script that collect some data from various sources, put them into a structured JSON and call a web service passing that JSON file.
I have a problem with null values in some of these fields ...
This is a snippet of my code:
…
Carlo Viola
- 3
- 3
0
votes
1 answer
To undefine in .bbappend shell function defined in .bb file
One .inc file included in some image-.bb file defines shell function for Bitbake task.
Let's concentrate here merely on this shell function, asigned Bitbake task is out of scope.
I wonder how to undefine this shell function in .bbappend file (other…
user5494920
0
votes
1 answer
The 'pattern' parameter (undef) to DateTime::Format::Strptime::new was an 'undef', which is not one of the allowed types: scalar scalar
I'm currently running into an issue getting perl cgi script browser display on my local machine (http://localhost:8080/Monitoring/www/user_status.xml.pl?user=xxxxxx). As it was a first install of Perl I understand there might be missing libraries so…
dale
- 439
- 3
- 11
- 28
0
votes
1 answer
Spreadsheet::ParseExcel $cell->value() returning undef
I am new to perl and having trouble with the spreadsheet excel parser module.
WHen I use $cell->value() on its own line, there appears to be no problem, however when I try to use this to insert the value into an array, it returns undef, code show…
James Jiimmy
- 49
- 1
- 11
0
votes
2 answers
Why does this string undef check return true?
my $line = "hello";
print ($line == undef);
The check should be false since $line is not undefined (I defined it in the first line). Why is this code snippet printing out '1'?
santi
- 77
- 2
- 4
0
votes
1 answer
Facebook connected but /me user is an empty object
I used the example from the facebook documentation but after granting facebook permission to connect I cannot get any user info from the user object. The user is defined but all its attributes are null. Here is my code:
…
-1
votes
1 answer
Perl debugging: Variable being set to `1` is set to `undef` unexpectedly
Note: Please read carefully; it's odd (unless I have tomatoes on my eyes)
I was changing a program of mine when it suddenly stopped to work as intended, and I failed to find the reason.
Eventually I found it; please consider this Perl debugger…
U. Windl
- 3,480
- 26
- 54
-1
votes
2 answers
Is there a ten element limit to the perl @_ array? In passing eleven arguments to my sub, the eleventh argument is always undef
Here's my sub that exhibits the problem:
sub merge_dat {
my($new_file_name,
$existing_file_name,
$output_file_name,
$start_elaphrs,
$end_elaphrs,
$time_adjust,
$existing_file_orig_name,
…
eggwad
- 1
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