大约有 44,000 项符合查询结果（耗时：0.0487秒） [XML]
When should I use perror(“…”) and fprintf(stderr, “…”)?
...
perror(const char *s): prints the string you give it followed by a string that describes the current value of errno.
stderr: it's an output stream used to pipe your own error messages to (defaults to the terminal).
Relevant:
char *stre...
SQL WHERE.. IN clause multiple columns
...a derived table from the subquery, and join table1 to this derived table:
select * from table1 LEFT JOIN
(
Select CM_PLAN_ID, Individual_ID
From CRM_VCM_CURRENT_LEAD_STATUS
Where Lead_Key = :_Lead_Key
) table2
ON
table1.CM_PLAN_ID=table2.CM_PLAN_ID
AND table1.Individual=table2.Indi...
jQuery get selected option value (not the text, but the attribute 'value')
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04/2020: Corrected old answer
Use :selected psuedo selector on the selected options and then use the .val function to get the value of the option.
$('select[name=selector] option').filter(':selected').val()
Side note: Using filter is better then using :sele...
Extracting an attribute value with beautifulsoup
...have a question about parsing the output which i a long bunch of non-ASCII chars but I will ask this in a separate question.
– Barnabe
Apr 10 '10 at 7:33
3
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C: Run a System Command and Get Output? [duplicate]
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#include <stdio.h>
#include <stdlib.h>
int main( int argc, char *argv[] )
{
FILE *fp;
char path[1035];
/* Open the command for reading. */
fp = popen("/bin/ls /etc/", "r");
if (fp == NULL) {
printf("Failed to run command\n" );
exit(1);
}
/* Read the output a ...
How do you implement a class in C? [closed]
...n(Object *self);
/// Person.h
typedef struct Person {
Object obj;
char *name;
} Person;
int Person_init(Person *self, char *name);
int Person_greet(Person *self);
int Person_clean(Person *self);
/// Object.c
#include "object.h"
int Object_init(Object *self)
{
self->uuid = uuid_new...
CHECK constraint in MySQL is not working
...GER `test_before_insert` BEFORE INSERT ON `Test`
FOR EACH ROW
BEGIN
IF CHAR_LENGTH( NEW.ID ) < 4 THEN
SIGNAL SQLSTATE '12345'
SET MESSAGE_TEXT := 'check constraint on Test.ID failed';
END IF;
END$$
DELIMITER ;
Prior to MySQL 5.5 you had to cause an error, e.g. ca...
Detecting which UIButton was pressed in a UITableView
...)metaData:(id)target
Enjoy
#import <objc/runtime.h>
static char const * const kMetaDic = "kMetaDic";
#pragma mark - Getters / Setters
- (id)metaData:(id)target {
return objc_getAssociatedObject(target, kMetaDic);
}
- (void)setMetaData:(id)target withObject:(id)newObj {
...
string.split - by multiple character delimiter
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This presupposes, that there are both characters right? What if I want to split by either "[" or "]"? From my tests so far I guess thats a different story, right?
– C4d
Mar 7 '16 at 15:28
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Specifically, what's dangerous about casting the result of malloc?
...f. Here's an example code fragment for discussion purposes.
main()
{
char * c = (char *)malloc(2) ;
printf("%p", c) ;
}
Suppose that the returned heap pointer is something bigger than what is representable in an int, say 0xAB00000000.
If malloc is not prototyped to return a pointer, the ...