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-1

I want to write some logs in file.

This is my Code:

FILE *writefile = fopen((Dir + FileName).data(), "at");
if (writefile)

 fprintf(writefile, log.data());
 fclose(writefile);

It surely works the first time when I try to write.

This code is executed in networking system, but it is executed in no connection status.

So, it keeps writing log "Try Connct" in every sec.

This is the image what I want to write

I can see these log on my console.

In image, I try to write log over 11:10:00.

But in File, it was not written until 11:06:00.

I try to debug my code,

This is the image in debugging

Why this happens?

---Addition---

I try to print error. So, I used perror.

I got Error : Too many open files.

But Why? Obviously I closed file, as you can see in my code.

c++

share|improve this question

edited Mar 25 at 3:01

Retalia K

asked Mar 25 at 2:30

Retalia KRetalia K

279

closed as off-topic by Max Vollmer, user4581301, Baum mit Augen♦ Mar 25 at 23:08

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "Questions seeking debugging help ("why isn't this code working?") must include the desired behavior, a specific problem or error and the shortest code necessary to reproduce it in the question itself. Questions without a clear problem statement are not useful to other readers. See: How to create a Minimal, Reproducible Example." – Max Vollmer, user4581301, Baum mit Augen

If this question can be reworded to fit the rules in the help center, please edit the question.

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I don't know why fopen() is failing, but you can get a hint about why it fails by checking the value of errno immediately after fopen() returns NULL (or, perhaps more conveniently, by calling perror("fopen") at that point, to see what error-message gets printed)
  
  – Jeremy Friesner
  Mar 25 at 2:36
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @JeremyFriesner Okay, I'll try to print error. Thanks
  
  – Retalia K
  Mar 25 at 2:42
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Maybe one of Dir or FileName have changed. Maybe your antivirus is getting in the way.
  
  – drescherjm
  Mar 25 at 2:51
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I got Error : Too many open files. But Why? Obviously I closed file As you can see in my code.
  
  – Retalia K
  Mar 25 at 3:00
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Your error might just be a symptom of an underlying problem elsewhere in your code. Try to create a minimal reproducible example, as right now we can only poke in the dark and do guess work. Also please don't screenshot error messages, debug information or code. Include any textual information as text, not as image. Thanks!
  
  – Max Vollmer
  Mar 25 at 3:06
  

  
  
  
  

 | 
show 5 more comments

-1

I want to write some logs in file.

This is my Code:

FILE *writefile = fopen((Dir + FileName).data(), "at");
if (writefile)

 fprintf(writefile, log.data());
 fclose(writefile);

It surely works the first time when I try to write.

This code is executed in networking system, but it is executed in no connection status.

So, it keeps writing log "Try Connct" in every sec.

This is the image what I want to write

I can see these log on my console.

In image, I try to write log over 11:10:00.

But in File, it was not written until 11:06:00.

I try to debug my code,

This is the image in debugging

Why this happens?

---Addition---

I try to print error. So, I used perror.

I got Error : Too many open files.

But Why? Obviously I closed file, as you can see in my code.

c++

share|improve this question

edited Mar 25 at 3:01

Retalia K

asked Mar 25 at 2:30

Retalia KRetalia K

279

closed as off-topic by Max Vollmer, user4581301, Baum mit Augen♦ Mar 25 at 23:08

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "Questions seeking debugging help ("why isn't this code working?") must include the desired behavior, a specific problem or error and the shortest code necessary to reproduce it in the question itself. Questions without a clear problem statement are not useful to other readers. See: How to create a Minimal, Reproducible Example." – Max Vollmer, user4581301, Baum mit Augen

If this question can be reworded to fit the rules in the help center, please edit the question.

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I don't know why fopen() is failing, but you can get a hint about why it fails by checking the value of errno immediately after fopen() returns NULL (or, perhaps more conveniently, by calling perror("fopen") at that point, to see what error-message gets printed)
  
  – Jeremy Friesner
  Mar 25 at 2:36
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @JeremyFriesner Okay, I'll try to print error. Thanks
  
  – Retalia K
  Mar 25 at 2:42
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Maybe one of Dir or FileName have changed. Maybe your antivirus is getting in the way.
  
  – drescherjm
  Mar 25 at 2:51
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I got Error : Too many open files. But Why? Obviously I closed file As you can see in my code.
  
  – Retalia K
  Mar 25 at 3:00
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Your error might just be a symptom of an underlying problem elsewhere in your code. Try to create a minimal reproducible example, as right now we can only poke in the dark and do guess work. Also please don't screenshot error messages, debug information or code. Include any textual information as text, not as image. Thanks!
  
  – Max Vollmer
  Mar 25 at 3:06
  

  
  
  
  

 | 
show 5 more comments

I want to write some logs in file.

This is my Code:

FILE *writefile = fopen((Dir + FileName).data(), "at");
if (writefile)

 fprintf(writefile, log.data());
 fclose(writefile);

It surely works the first time when I try to write.

This code is executed in networking system, but it is executed in no connection status.

So, it keeps writing log "Try Connct" in every sec.

This is the image what I want to write

I can see these log on my console.

In image, I try to write log over 11:10:00.

But in File, it was not written until 11:06:00.

I try to debug my code,

This is the image in debugging

Why this happens?

---Addition---

I try to print error. So, I used perror.

I got Error : Too many open files.

But Why? Obviously I closed file, as you can see in my code.

c++

share|improve this question

edited Mar 25 at 3:01

Retalia K

asked Mar 25 at 2:30

Retalia KRetalia K

279

FILE *writefile = fopen((Dir + FileName).data(), "at");
if (writefile)

 fprintf(writefile, log.data());
 fclose(writefile);

share|improve this question

edited Mar 25 at 3:01

Retalia K

asked Mar 25 at 2:30

Retalia KRetalia K

279

share|improve this question

edited Mar 25 at 3:01

Retalia K

asked Mar 25 at 2:30

Retalia KRetalia K

279

asked Mar 25 at 2:30

Retalia KRetalia K

279

asked Mar 25 at 2:30

Retalia KRetalia K

279

1 Answer
1

active

oldest

votes

0

You have a resource leak in your program. There are too many open/dup/fopen/stream::open/pipe/connect/accept/socket calls without a matching close/fclose/~stream/stream::close.

In the case of FILE leak, you can avoid it by one of:

• use ofstream instead of FILE in all your code. It will automatically close the file when it gets out of scope.


• use unique_ptr of FILE with a custom deleter. This will close the file automatically, when it gets out of scope.

Unfortunately there is no easy way to find this leak. The best way is to avoid it from the beginning, by using RAII all the way with std::stream, std::unique_ptr, and boost asio. Since the code didn't follow this rule, the only way out is to search for fopen (and others) through the code, and make it use RAII, possibly with unique_ptr.

share|improve this answer

answered Mar 25 at 3:29

Michael VekslerMichael Veksler

5,9141824

add a comment | 

0

You have a resource leak in your program. There are too many open/dup/fopen/stream::open/pipe/connect/accept/socket calls without a matching close/fclose/~stream/stream::close.

In the case of FILE leak, you can avoid it by one of:

• use ofstream instead of FILE in all your code. It will automatically close the file when it gets out of scope.


• use unique_ptr of FILE with a custom deleter. This will close the file automatically, when it gets out of scope.

Unfortunately there is no easy way to find this leak. The best way is to avoid it from the beginning, by using RAII all the way with std::stream, std::unique_ptr, and boost asio. Since the code didn't follow this rule, the only way out is to search for fopen (and others) through the code, and make it use RAII, possibly with unique_ptr.

share|improve this answer

answered Mar 25 at 3:29

Michael VekslerMichael Veksler

5,9141824

add a comment | 

0

You have a resource leak in your program. There are too many open/dup/fopen/stream::open/pipe/connect/accept/socket calls without a matching close/fclose/~stream/stream::close.

In the case of FILE leak, you can avoid it by one of:

• use ofstream instead of FILE in all your code. It will automatically close the file when it gets out of scope.


• use unique_ptr of FILE with a custom deleter. This will close the file automatically, when it gets out of scope.

Unfortunately there is no easy way to find this leak. The best way is to avoid it from the beginning, by using RAII all the way with std::stream, std::unique_ptr, and boost asio. Since the code didn't follow this rule, the only way out is to search for fopen (and others) through the code, and make it use RAII, possibly with unique_ptr.

share|improve this answer

answered Mar 25 at 3:29

Michael VekslerMichael Veksler

5,9141824

add a comment | 

You have a resource leak in your program. There are too many open/dup/fopen/stream::open/pipe/connect/accept/socket calls without a matching close/fclose/~stream/stream::close.

In the case of FILE leak, you can avoid it by one of:

• use ofstream instead of FILE in all your code. It will automatically close the file when it gets out of scope.


• use unique_ptr of FILE with a custom deleter. This will close the file automatically, when it gets out of scope.

Unfortunately there is no easy way to find this leak. The best way is to avoid it from the beginning, by using RAII all the way with std::stream, std::unique_ptr, and boost asio. Since the code didn't follow this rule, the only way out is to search for fopen (and others) through the code, and make it use RAII, possibly with unique_ptr.

share|improve this answer

answered Mar 25 at 3:29

Michael VekslerMichael Veksler

5,9141824

share|improve this answer

answered Mar 25 at 3:29

Michael VekslerMichael Veksler

5,9141824

answered Mar 25 at 3:29

Michael VekslerMichael Veksler

5,9141824

answered Mar 25 at 3:29

Michael VekslerMichael Veksler

5,9141824